Qbittorrent: IO Errors popping up out of nowhere

[SarreqTeryx]

EDITED BY @sledgehammer999
Libtorrent bug link: https://code.google.com/p/libtorrent/issues/detail?id=406
Read that link carefully and this one too before posting "me too" reports.

ORIGINAL POST TEXT FOLLOWS

I've suddenly been getting this error on several torrents the past day or so

25/12/2012 22:31:58 - An I/O error occured, 'blanketyblank' paused. 25/12/2012 22:31:58 - Reason: blanketyblank file (C:/Users/Sarreq Teryx/Downloads/ut\blanketyblank.mkv.!qB) error: Used to indicate that an operation cannot continue without blocking for I/O

[ask21900]

I am also getting this for all torrents. Issue #130 appears to be the same and says it was solved, but does not reference details.

Win7 64bit
v3.0.6

[Gelmir]

This messages is one of standard messages defined by Windows itself.
http://msdn.microsoft.com/en-us/library/windows/desktop/ms681388%28v=vs.85%29.aspx
ERROR_CANT_WAIT it is.
This was discussed on old bugtracker with no resolution: https://bugs.launchpad.net/qbittorrent/+bug/825092

I cannot reproduce that anyhow.

[Gelmir]

Ok. I've bumped into the bug. Looks like it usually triggers on big torrents 20+ GiB with average file size ~ 1GiB. Seeding, as it seems, is not affected, only downloading.
The message log mentions only one specific file regardless of whether it is checked or not.
As a side effect you can lose download paths for all torrents.
I've tried libtorrent 0.16.[4,5,6] - all the same.

Trying libtorrent aio branch, had to do some patching.
Edit: forget about lt_aio, too much work; this will require a lot more effort than fixing a bunch of ifdefs.

---

---

Interesting. I've left my PC running over night, building stuff. In the morning I've moved torrents, broken with the side effect, to their original locations and rechecked. Now everything works fine.

My guess would be that OS cache for broken items has expired. I'll try to contact LT devs regarding this issue anyway.
From my perspective ERROR_IO_PENDING and ERROR_CANT_WAIT are not errors, but info messages, and file_error_alert from lt alert class should support filtering like most alerts.

---

P.S. Typicial side effect errors look like this:

07/01/2013 13:50:42 - Reason: torrent_name fast resume rejected: missing or invalid 'file sizes' entry
07/01/2013 13:50:41 - Reason: torrent_name fast resume rejected: mismatching file timestamp

[ask21900]

For anyone else that has this issue, a solution in the old bug tracker seems to solve the issue (albeit annoying):

1. Create a zip of the files
2. Delete the original files
3. Unzip the archive
4. Restart the torrent

Every torrent that this issue has happened on for me (20+ torrents), this resolved the issue. So far, I have only had to do this process once per torrent in which the error occurred.

[Myritekk]

Adding my own information here for the sake of data.

I am getting the exact same error on one of my torrents on qbittorrent 3.0.6. It was added newly, 40+GB, and around 17GB downloaded gave me the error message in the original issue. I tried moving it to C:/ (as per suggestions that the file name was too long) - didn't help.

None of my seeding torrents were affected, haven't tried downloading any other files.

Currently attempting ask21900's fix.

EDIT: Forgot to thank you for coming back and telling us what you did. Too often people forget to do this.

[ask21900]

Also for the sake of tracking, I have now had this issue occur with a 7.7 GB and a 4.3 GB torrent as well as larger sized (20+) ones.

[Gelmir]

Does a reboot help? I think this might be related to OS cache, and there are only two ways to flush it:

1. Reboot
2. Using an undocumented windows "feature", which is probably a bug.

P.S. I've reported this upstream to libtorrent bugtracker.

[Gelmir]

sledgehammer999, can you try adding this patch http://libtorrent.svn.sourceforge.net/viewvc/libtorrent/branches/RC_0_16/src/file.cpp?r1=7844&r2=7826 to official builds?

P.S. https://code.google.com/p/libtorrent/issues/detail?can=2&start=0&num=100&q=&colspec=ID%20Type%20Status%20Priority%20Milestone%20Owner%20Summary&groupby=&sort=-id&id=406

[Gelmir]

Is this still an issue with 3.0.7/3.0.8?

[Myritekk]

Two things:

-Under 3.0.6, a reboot did not help. I ran into the issue twice more, and a reboot did not solve the issue.. ask21900's fix did work. For some reason I forgot to update here.

-Under 3.0.7/3.0.8, I've not yet ran into the issue but I haven't started any large sized torrents (which is usually where the issue seemed to occur).

[sledgehammer999]

This seems to have been solved in libtorrent 0.16.7(which is used for 3.0.7 and 3.0.8 ). I will close this. If you encounter the error again, please reopen this bug (or creatte another).

Thanks @Gelmir for reporting it upstream. (I didn't reply to your question because I didn't get any notification).

[Gelmir]

Well, I've just got another one on 150 GiB torrent. So this is not fixed.

[sledgehammer999]

Reopening then. @Gelmir will you report upstream?

[Gelmir]

Already done: https://code.google.com/p/libtorrent/issues/detail?id=406

I'm currently using a patch which extends the original fix. It ignores those errors wherever possible. So far, so good. I'm gonna finish the 60 GiB DL, reboot and recheck to see if my fix has no side-effects.

[Gelmir]

My patch partially works. It allows DL to continue, but after recheck some pieces are corrupt (~1% usually).

[Gelmir]

Mingw builds seem to be unaffected. I'm gonna be REALLY disappointed if this is a compiler bug.

[Gelmir]

@sledgehammer999
This seems to be resolved https://code.google.com/p/libtorrent/issues/detail?id=406

This patch should be applied to 0.16.7

[sledgehammer999]

ok. I will use it in next qbt release.

[jordanade]

I get this with files that are only around 600MiB. It usually happens after the file has downloaded halfway or so.

[jordanade]

I can unpause the torrent after this happens and it will start working again, for a while. But then it happens again. Once the torrent is downloaded 99%, it will happen as soon as qBit tries to write anything to the disk, so there's no way to complete the torrent.

Also, each instance involves the creation of 100s of identical errors ("an operation cannot continue without blocking for I/O"), at a rate of 20 per second. After a few seconds the torrent is paused.

Another workaround is to finish downloading with uTorrent.

[ask21900]

FWIW: I was able to duplicate this issue on a Windows Vista Machine, and on a Windows 7 machine on demand by opening a video that had not completed yet. I was able to watch the video up until a missing part, at which time the video errored out (freezing) and the torrent paused with this error (requiring the fix that I posted earlier).

I should also note, that while I can duplicate this error by doing that, I have also received this error while not (personally) accessing anything. Maybe the issue lies with Windows accessing the file while downloading (indexing or something)?

Also, I find it unlikely (although not impossible) that it is attributed to large torrents as I have found this on a torrent about 10MB.

[sledgehammer999]

As said earlier, the bug has been fixed in libtorrent. It will be included in next release of qbittorrent(3.0.9). If after that the bug persists, then feel free to comment.

[jordanade]

Hey sledge when can we expect 3.0.9? This is a real PITA. Thanks!

[Gelmir]

I hit the bug again
Any of you, experiencing the same problem, have MSE AV installed?

[zafod]

It seems that this bug is related to fragmentation in the torrent content. I used Contig utility from windows sysinternals http://technet.microsoft.com/en-us/sysinternals/bb897428.aspx on file mentioned in error and it showed that file have ~1600 fragments. After defragmenting the file torrent had finished without any errors. So as a workaround it's possible to defragment files causing the errors.

[jordanade]

Just pausing, copying, deleting, renaming the copy to match the original is
enough to fix it.

On Wed, Feb 13, 2013 at 2:48 AM, zafod [email protected] wrote:

It seems that this bug is related to fragmentation in the torrent content.
I used Contig utility from windows sysinternals
http://technet.microsoft.com/en-us/sysinternals/bb897428.aspx on file
mentioned in error and it showed that file have ~1600 fragments. After
defragmenting the file torrent had finished without any errors. So as a
workaround it's possible to defragment files causing the errors.

—
Reply to this email directly or view it on GitHubhttps://github.com/qbittorrent/qBittorrent/issues/294#issuecomment-13477892.

[ticolensic]

Not sure yet, but lately it was an issue for me too. I got a feeling that it was something to do with jumping back and forth a file, trying to read and at the same moment write to it. I limited the upload rate to get rid of accidental reads, and I was almost able to download it (99.9%). Unfortunately, you cannot loose all the uploads at once, and seems it is an incorrect solution, but it might work for someone.

[sledgehammer999]

For anyone wanting to try out the latest of libtorrent code in case it has resolved this try my alpha build found here: http://qbforums.shiki.hu/index.php?topic=1747.msg5814#msg5814

[ask21900]

I no longer have this problem since I switched my torrenting to an Ubuntu machine, but before I did I learned a little more that you might find useful.

I was able to recreate this issue by attempting to view a video prior to it completing. Every file that I opened would run smoothly until I attempted to view a section of the video that hadn't downloaded yet. Immediately qBitTorrent threw this exact error.

I would like to point out that I have also received this error when I did not personally access a file so it makes me think that Windows is accessing files for whatever reason (to pull thumbnails maybe?) and that is causing (or at least contributing to) the error. It seems like @merinoffff is on the right track.

[ticolensic]

We can sum up now. I was able tto have it downloaded only after I had done defrag. I'll see the code, maybe I'll find anything if I'm lucky.

[jordanade]

Still getting the error in 3.0.9.

[sledgehammer999]

The bug is still not fixed in libtorrent. Reposting the bug link: https://code.google.com/p/libtorrent/issues/detail?id=406 :s

[s-ol]

I am still having this problem with QBIttorrent v3.0.8 on Windows 7 x64.

[mcozire]

Just got error today out of know where on three different torrents I tried. Previously was working fine. v3.0.9

[Poilaucul]

I have the same issue on a 60GiB torrent.

[sledgehammer999]

@Poilaucul what OS are you using?

[mcozire]

Windows 7 64bit. Thanks.

[Poilaucul]

@sledgehammer999 Windows 7 Ultimate x64

[oakkitten]

the bug is still present in 3.1.0alpha (libtorrent 0.16.8.0)
win7 32bit, mostly small, under 7gb, torrents consisting of 400mb-1.5gb files

[Poilaucul]

Still get this error on v3.0.11.

[henryk123]

Not fixed in 3.0.11.
You can reproduce this error by D/L http : / / torrent . zoink . it/Dexter.S08E06.PROPER.720p.HDTV.x264-IMMERSE.[eztv] . torrent

FDM downloaded this torrent properly but shown the following errors:
Failed to receive the valid response from the tracker. (http://www.h33t.com:3310/announce)
Dexter.S08E06.PROPER.720p.HDTV.x264-IMMERSE.mkv (http://www.h33t.com:3310/announce)
(-1) This is usually a temporary error during hostname resolution and means
that the local server did not receive a response from an authoritative
server (2)
Failed to receive the valid response from the tracker. (udp://open.demonii.com:80)
Dexter.S08E06.PROPER.720p.HDTV.x264-IMMERSE.mkv (udp://open.demonii.com:80)
(0) timed out (2)
Failed to receive the valid response from the tracker. (udp://tracker.coppersurfer.tk:80)
Dexter.S08E06.PROPER.720p.HDTV.x264-IMMERSE.mkv (udp://tracker.coppersurfer.tk:80)
(0) timed out (2)

So probably it's something connected to error handling in qbittorrent

[Gelmir]

We know this is still an issue. But it's not something easily fixable and debuggable on our side.

[jonheg]

Hi all!
In Qbittorrent v3.0.6, when getting these errors, i can pause the torrent, press "Force recheck" and start torrent again without errors. Dont know how this works on other versions.

[Gelmir]

@sledgehammer999, I'll try to see if session_settings::lock_files can overcome this. Using this option will remove any possibility of file preview though.

P.S. There's an interesting option in libtorrent:

        // if this is set to true, the memory allocated for the
        // disk cache will be locked in physical RAM, never to
        // be swapped out
        bool lock_disk_cache;

[sledgehammer999]

If lock_files solves it, then the libtorrent author might have a better idea on what is happening and actually solve the problem.

[Gelmir]

Damn. Testing this is real pain. lock_files wants exclusive access for both reads and writes, so I can't do anything with files, while libtorrent is accessing them.

[Envisign]

This bug happens on any size torrent for me. Once or twice a day leaving qBittorrent running 24 hours.

Using v3.1.1.1

[seeker]

I too am having this issue with 3.1.9 on Windows 7 x64.

One torrent with a single large file (85 GB) works fine.
However, three other torrents of around 100G, with about 1000 files ranging from 2 MB to 2GB cause IO errors, an pause after a few seconds.

[sledgehammer999]

I only got this once with foobar2000. It library indexing function interfered with the downloading material, because it contained audio files and I saved the torrent in the indexing path of foobar2000. So some of you may encountered this because some program was indexing the files in the background.

[sledgehammer999]

@svnpenn Maybe. I don't know. Is this on by default on Windows XP? If yes, I have never encountered any problems with it. How about later Windows versions?

[seeker]

I do not have windows search installed and the indexing service and other search related services are disabled.
However I will check to see if the Anti-Virus (Avast!) might be the cause.

[ghost]

@dozedoff are you saying you turned Windows Search off?

http://sevenforums.com/tutorials/25343-windows-search-turn-off.html

[seeker]

Yes, I have rechecked and confirmed that Windows Search is disabled.

• Disabling the Anti-Virus did not help
• Moving the save location to drive root and shortening the save folder to one letter did not help
• The reported IO error was "The system cannot find the path specified"

Interesting enough downloading works without issues on Ubuntu 13.10 to a ext4 partition.
However when accessing the download folder over Samba, the torrent folders were mangled (6 uppercase Alphanumeric symbols followed by a tilde and then another uppercase alphanumeric symbol).
The file names within the torrents folder where correct.

[Belove0]

@dozedoff That sounds like an unrelated I/O error to me.
The torrent may contain a directory or filename that has invalid characters or is too long. Based on your Ubuntu/Samba result I would try, when downloading the torrent in Windows, totally renaming the root directory/folder name in the file list of the Add Torrent dialog to see if that resolves it. If so, you may want to search for or start another bug to discuss the issue of pathnames incompatible with the file system or OS in torrents.

[sledgehammer999]

As a note: The user from #1133 indicates that this error happens mainly when the piece size is 8MB.

[ghost]

Okay, I’ll be that guy. What the F is piece size, and does the program have a setting to change it?

[sledgehammer999]

@svnpenn offtopic: The piece for any given torrent cannot change, unless you want to produce a different torrent. Highlight a torrent and click the "general" button. For more info search google on how a torrent works. (hint: each torrent is divided into equal size pieces)

[Giszmo]

I guess many come here for the I/O error part, just like me. The notification pops up and disappears quickly on my debian qBittorrent 3.1.9.2 and it complains about a file or folder it can not find. The seeding torrent is paused. I hit resume and after a while the error returns and the torrent is paused again.

In this case it is a UI issue though. Prior versions would have started the download all over again upon a missing file (that I moved out of the folder). Now it just gives me a nasty IO error. This should come immediate upon hitting resume or better immediate upon startup of qB or upon removing the file underneath a running qB.

[sledgehammer999]

@Giszmo Don't hijack this issue. You are talking about a different error. I really doubt you get the same are described in the first post. (ie the same "Reason").
You can look up your reason in the log. (view->execution log).

[sonjagiraffi]

I'm getting a very similar error using Deluge. I'm fairly sure it also uses libtorrent, so I thought I'd mention it. If not, I apologize, I really don't know how these things work, but I wanted to help :)

Edit: Switching to qbittorrent solved the issue it seems..

v3.1.10
win7 SP1 64b

[ghost]

v3.1.9.2 has the same issue with a piece size of 2MB for a torrent of 16GB. This is a very common issue for large torrents.

[sledgehammer999]

@Phibonacci FYI latest is v3.1.11. Can you test if this still happens if you disable os cache in the advanced settings? (this is available in v3.1.11)

[ghost]

I have a shared NTFS partition Between Windows 7 (Qbittorrent 3.1.9.2) and Ubuntu 13 (Qbittorrent 3.0.11). I added the same torrent and reused the partly downloaded files and I did not get any error so far.
I will try the v3.1.11 and to disable the OS cache when I will be back on Windows.

Edit: No more bug for this torrent on Windows. It has either something to do with the reboot or with the fact I used Qbittorrent on linux for the same torrent and the same path.

[ghost]

this error appears when you access the file while it is downloading
i think the file must be locked just u can see it and open it but the system cannot change it until qbittorrent stop accessing the file
this will solve this error
you can exit qbittorrent and open it again and you can resume the download as normal
i think utorrent just make the same strategy of locking the files while downloading
-by the way when you open the folder that has the files it may make the same thing; because windows begin to access any media files to add preview thumbnail to the file which made it looks not accessed from qbittorrent and the error appears

[Hietamaki]

I just upgraded from 3.0.9 to 3.1.11 and the I/O problem... seems to be fixed. I have OS cache enabled.

So thanks!

[ripdog]

3.1.12, this problem keeps occurring on a torrent of size 34.6 GiB with a piece size of 8MiB. IO Error "Out of Space" on a 1TB free volume, torrent pauses. On resume, qbittorrent crashes. Restart qBittorrent, and it works fine for a while, then problem happens again.

[chrishirst]

OS??
Execution log entries?
Using OS caching?
Anti-Virus?

[sledgehammer999]

@ripdog You said yourself that your error is different from the one posted here. So why do you hijack this thread? Anyway, try disabling OS cache from the advanced settings and see if that helps.

[reijikun]

Mine, a rar with 6,3GB size (previously stuck at 99.9%), fixed by upgrading qB 3.1.0.0 to qB 3.2 with unchecked OS cache. Win7 64bit.

[reijikun]

Excuse me? I don't get what did you say.

2015-05-28 4:34 GMT+07:00 nathanvl [email protected]:

CAN THIS PLEASE BE SOLVED ONCE AND FOR ALL THIS BUG IS 3 YEARS OLD WHAT
THE FUCK

Reply to this email directly or view it on GitHub
https://github.com/qbittorrent/qBittorrent/issues/294#issuecomment-106085996
.

[nathanvl]

I was quite annoyed when encountering this bug. Seeing it was so old and never solved really made me furious. I guess that's what can come with free software, if no one with the necessary skills cares enough to try to solve a bug they do not experience themselves, it doesn't get fixed. That made me so enraged I reacted like that, instantly realizing it was over the top, and removing it. Glad you still got the message though.

[chrishirst]

I was quite annoyed when encountering this bug. Seeing it was so old and never solved

That's the problem with reports that are 'hijacked' by people reporting symptoms that may have different causal factors. It looks like they are not solved, whereas in reality, there has been multiple disparate problems that all have been 'fixed'.

[sledgehammer999]

You guys don't seem to have read the whole thread. This is a libtorrent bug. I will re-link the bug report here(and I'll edit the original issue too). Please go there and nudge arvidn(libtorrent author) to try to fix this. This issue is being kept open, in case arvidn proposes a patch so I'll have people to tag and test my patched builds. Or to perform logging tests(requeted by arvidn). I cannot fix this.
Link: https://code.google.com/p/libtorrent/issues/detail?id=406

[Extrapolator214]

I reproduced it on Windows 8:

1. Click on magnet link
2. click OK to start download BEFORE metadata is retrieved
3. I/O Error

If you wait for a bit until metadata is fetched then the download starts normally.
P.S. I download on NTFS partition shared between Win and Kubuntu

[sledgehammer999]

Removed troll comment by @hatem-badawi

[MonsterMMORPG]

I just had it at 3.2.1 with 100GB torrent file

windows 8.1 x64 all updates done

other torrent files downloading fine

[barrygear]

Using v3.2.0 to 3.2.3 on OSX and I had never seen this issue. Then suddenly after I changed my download dir from a local drive to an NFS mounted drive, I was getting this with every other torrent. From 30mb in size to 6gb. I loaded the same torrents, with the same destination into Transmission and it worked without issue.
I enabled OS Cache to see if that helped and it didnt. I even enabled IPv6 (yes I have functioning v6)

[nbergont]

Still have this problem on V3.2.4 with Windows 7 64bits :

• "OS Cache" option don't seem to solve problem.
• If you try to visualise a torrent (movie) before it finished this will enchance bug emergence.
• My solution is to restart qBittorent and "force check" the torrent witch fail.
• Seem a strange Windows 7 file acces bug (concurent read write access)...

[DanAVD]

upgraded from 3.2.4 to 3.2.5 and started having the problems. fine under 3.2.4 for me

[dmitry]

3.3.0-beta has the same issue in linux (mint).

[ultranuovo]

It looks like qbittorrent is jumpy about file locking. I had to disable avast AV, serviio and media library automatic scan on download folder and then I/O errors went away. As soon something is touching files being downloaded, qbittorrent reports I/O error.

[VincentThompson]

fix qbittorrent I/o error solution Jan 2016

Tried various suggestions including dskchk, changing my anti-virus, running the program as administrator, changing the drive 'D' ownership from SYSTEM to Administrator (using drive D for torrent downloads) etc. Eventually what seems to have been responsible for the error was the max number of connections which I reduced from 500 to 420. Seems this is what causes the I/o error as since before posting I have run qbittorrent error free for about 10 hours. Hope this helps you as I also tried installing most of the other torrent clients which also failed with read errors (originally was using utorrent).

[VincentThompson]

Thought about this a bit further. I certainly seems to be the number of connections which is responsible, so perhaps that is going to be a variable for people depending on their interconnection speed, (if you are using a proxy service to disguise your on line activity different counties have slower or faster connection), so the solution may simply be to just keep lowering the max number (global) connections until your particular downloads become stable. This might well be the answer for errors cropping up if you are using a different client torrent.

[VincentThompson]

After further testing this IS the solution. Depending on the proxy connection the settings ARE VIARABLE. One of the torrents on another location brought up the error until I stabilised it by bringing the max global connections down to 100 and the max torrent connections to 80. :)))

[sledgehammer999]

@arvidn can you look at the very 1st post and then at the 3 comments above me. Does it give you any idea on how to solve it by checks in libtorrent?

[arvidn]

If it is the number of open handles the closest I can think of as a solution would be to improve the default limits in libtorrent. On unix you get an EMFILE error code to indicate that you have too many file descriptors, and you can query the limits with rlimit(). I don't know of a way to query the limit of open handles on windows (but I was under the impression that the limit was very high).

This error is the ERROR_CANT_WAIT one? It's a bit of an unexpected place and error code to indicate that there are too many open handles. It's also a point where it's difficult to handle the error in a high-level reasonable way, say, close a few connections and try again. I suppose it could be handled by failing the write, close a few connections but keep downloading. It seems like there must be a better way though, to avoid it entirely in the first place.

[sledgehammer999]

Yes the ERROR_CANT_WAIT. You might want to read the bugreport on your previous bug tracker too. (see first post). I understand what you're saying above, but I can't be of any help.
If you do come up with a patch, I'll provide a build for users to test.

[VincentThompson]

Just to clarify - the I/O error I'm talking about is the read from disc one (sorry if I confused the issue). This read I/o is worded slightly differently for other torrent clients but it seems to be an issue affecting a large number of people all of a sudden which makes me suspect there is actually nothing wrong with the coding in the clients themselves. Some are blaming windows 7, their anti-virus etc, but I just can't help wondering if its the ISP providers themselves perhaps doing something with encrypted connections?. Could they have been legally forced to show some sort of compliance with measures designed to 'discourage' using proxy servers so torrents fail often with read errors in the belief that people will eventually give up?. Anyway to get mine to stabilise I'm reduced to one download with sometimes the global connections reduced to somewhere between 50 and 100, with the torrent connections set 5 below the global figure.

[VincentThompson]

The error I'm referring to in qBittorrent is 'An I/o error occurred for the torrent xxxxx. Reason reading p:1428 b: s: 524288 (read 0)) error: file too short'

[AgentRev]

Not sure if related to this issue, but I have been getting tons of I/O errors saying "Access denied" for a particular torrent. I managed to fix it by unticking "read only" in its destination folder's properties and letting Windows apply the change to all subfolders.

[nbergont]

I have disable (video) thumbnails in Windows 7 with ShellExView, and its seem to work for me (no i/o errors during 2 weeks).
I suspect Windows thumbnails process to acces file during download...

See more here :
http://superuser.com/questions/152272/how-do-i-disable-video-thumbnails-in-windows-7

[Jakoh]

It indeed appears to occur when a torrent is being accessed while it's downloading, to quote hatem-badawi.

I/O errors were popping up for me since a while.. until i discovered that i had Musicbee automatically updating my music library (from my music folder where the torrents were being saved). Disabling the continious monitoring of my folder just solved it for me.

[AlcatelOneTouch]

Qbittorent Version: 3.3.4 and now 3.3.6
OS -> Windows 10 Pro
CPU -> I7 3930k @4500 mhz
RAM: 16GB
Execution log entries -> Not possible, because when the error happens the client stops responding and then crashes.
Using OS caching -> No and Yes (I've tried both)
Anti-Virus -> Yes, ESET Smart Security V9 and no (I tried enabling and disabling).
Connection Speed -> 200Mbps down/200 Mbps up
Additional information -> I mainly seed, and this error happens while seeding.

Ok, this is seriously pissing me off.
As most private trackers are banning utorrent, now I've to use this.

Since I started using qbittorent, the message _An I/O error occurred for torrent 'abc'_ error starts spamming left and right after some time and the client just freezes but continues to upload (if I click anywhere on the client, the it stops working and crashes), and I've to restart the client.
With utorrent with the same amount of torrents on the same location, uploading at a higher speed for weeks, I never had any problem.

Do you know any way to solve this?

[thalieht]

This guy https://github.com/qbittorrent/qBittorrent/issues/294#issuecomment-170490952 says that lowering max global connections fixed it for him and some others said something about fragmentation. Maybe try using "Pre-allocate disk space for all files" but this will work on new downloads only. If you haven't already read whole issue for some other possible solutions.

[arvidn]

@sledgehammer999 version 3.3.4 and 3.3.6, which version of libtorrent is that?

[thalieht]

3.3.6 is Libtorrent 1.0.9+git f716aef5 according to the changelog

[thalieht]

and 3.3.4 is Libtorrent: 1.0.8+git 602dc02 according to the forum post

[AlcatelOneTouch]

Hello.

Just to say that the x64 version (qBittorrent-3.3.7-release-3.3.7-0-g88f5907-libtorrent1.0-x64-setup.exe) fixed all the I/O errors and program freezes I was experiencing with the x86 version while uploading at high speeds (100Mbps+), more information on this thread --> https://qbforums.shiki.hu/index.php/topic,4544.0.html

Since I installed the x64 version today (09h WEST), I've uploaded 741GB with no errors or freezes so far.

Regards.

[dontknowwhatimdoing]

I had this error and was able to fix. I'm on x64 Windows 10 using qBittorrent 3.3.10.

I don't know why the error occurs but I am able to "fix" it by changing the download folder to something else. Hope that helps someone.

[megapro17]

Keep getting this problem.

[Cleotus]

The fix that nbergont mentioned worked for me. v3.2.5 on Windows 7. Thanks everyone!

[Arvacon]

The solution of the https://github.com/qbittorrent/qBittorrent/issues/294#issuecomment-170490952, finally solved this issue for me. I just reduced that number from 500 to 420 and everything works fine now. Thank you my friend.

[Seeker2]

If the x64 version of qBT fixes the I/O errors and program freezes, then it was possibly a ram overload by the x86 version caused by downloading/uploading quickly (>5 MB/sec) and qBT's cache size growing too large.
Core libtorrent issue for ram+cache problem:
https://code.google.com/archive/p/libtorrent/issues/508
https://github.com/xlgjjff/libtorrent/issues/508
Similar example: https://github.com/qbittorrent/qBittorrent/issues/6594

[arvidn]

My impression is that it could be related to having too many handles open. The default limit on windows was set unreasonable high in previous versions of libtorrent. This was changed in libtorrent-1.1.3 and may fix this issue.

[insurw]

Sorry about my rant last week. I shouldn't post when annoyed. :(
Anyway, I think why I've gotten "I/O error. Access denied" sometimes is because:

• Episode torrents in folder A.
• Add season torrent and point it to folder A.
• Episode torrents are still active.
• Season torrent is also downloading a couple more episodes.

Result: Season torrent gets I/O error over and over again after seconds/minutes of running.
Regular downloading always works fine.

edit: Did a test but couldn't replicate it. Maybe I missed some step.

[JoshLambda]

I'm getting I/O errors with qB version 3.3.12 x64 on both Ubuntu + SSD and W10 + mechanical drive.

Even when I delete files and I change download location to a different physical drive then the I/O errors always happen on the same torrents (while downloading after recheck). I get the same result when running the client with admin rights.

So it doesn't seem to be an error related to filesystem integrity or write permissions or specific to an OS (unless my different filesystems on different physical drives and different OS are all corrupted).

[arvidn]

the errors on windows will be different than the ones on ubuntu. Do you know specifically which errors you get? error message or error code

[JoshLambda]

On Windows the error from Execution Log is :
5/17/2017 23:50 - An I/O error occurred, '<torrent name>' paused. <torrent name> file (<file name>) error: Access is denied
Both partial file and parent folder have "Full control" for Everyone so this doesn't make sense. I tried running the client as Administrator with same result.

[arvidn]

great, my theory is that on windows, you may get this error if you have too many file descriptors open, and libtorrent (prior to 1.1.3) would set an unreasonably high limit on how many files it would open. Which version of libtorrent are you using?

I would not expect the errors you see on Ubuntu to be related to the ones you see on windows. what errors do you see there?

[JoshLambda]

According to qbittorrent.org (current client version downloaded today) libtorrent version is libtorrent-rasterbar 1.0.11+gitbda4fd60c4c7. (Edit 1: according to the client itself, this is libtorrent 1.0.11.0)

Edit 2: I used TestLimit from Sysinternals and could create 16711570 handles. I'm surprised that libtorrent would use that many.

Edit 3: I used Process Explorer and there were 507 handles opened by qBittorrent when I/O error occurs. (I waited a bit and the handle count stays 500-ish.)

I can't check the errors on Ubuntu because I uninstalled the client since.

[redfellow]

I started getting this error as well last week. Windows 10 qBittorrent v3.3.12. As far as I can tell, this begun when I started to use a different (checked it, and it's healthy) disk for torrents. Old one was 1TB Samsung and new is a 4TB WD.

Couple of larger torrents error out and so far restarting qBittorrent and force-rechecking seems to work for a while, but when checking on the torrent again some hours later it's stuck in an errored state again.

Max connections: 400
Max active torrents: 10
Max connections per torrent: 100

[arvidn]

I just thought of an alternate theory. Is it the case that this error appears to happen only or more likely to large files?

I recall early versions of vista had a bug where a sparse file ended up having too many extents, the filesystem would break and the system would hang. Perhaps the underlying issue is just now surfaced as this error rather than hanging the system.

Has anyone seen this error when files are fully allocated?

[insurw]

Win10 Pro (Anniversary)
QB 3.3.12

The only situations it seems to happen for me as I wrote before is when completing a season folder that has missing episodes (i.e. before I've downloaded seperate episodes and then adding a season torrent to complete the season). But I made sure the episode torrents were removed in QB and it still happened, so that seems irrelevant.

_Another equivalent situation. I had with utorrent previously downloaded a torrent with a pack of files but only 5/7 files. I recheck the torrent with QB and the downloaded files show 99.9% and with a few MB "missing" (because of adjacent files). I try to download the missing MB, i.e. still only 5/7 files, but QB instantly gives I/O error._

It'll download for X seconds but then give the error:

An I/O error occurred, 'TorrentNAME' paused. TorrentNAME file (PATH\FILENAME.mkv.!qB) error: Access is denied

When the season torrent finally gets to 99.9% it won't run enough time to finish but will error right away. Restarting QB or Windows doesn't help. The only way I was able to finish the torrent was to delete the new partially downloaded file and its adjacent file which was at 99.9%.
I don't know. Maybe it was random reason. Why problems occur with computers feels so random sometimes. Like it's more magic/randomness that makes computers work than code.

What I've noticed it that every time before this I/O error happens QB shows "not responding" for X s and then explorer.exe crash and restart (noticeable because the Taskbar crashes).

From EventViewer: https://pastebin.com/2Qms7sUN

[oakkitten]

in my case, the error is completely gone on win10, i've been using qbt for months, large and small torrents, no problems. i do have the option to pre-allocate space for all files on, though it seems to be doing no good as i'm constanly having torrents abruptly stopped in the middle for lack of disk space.

[gth]

Is it possible to see the results of the Force Recheck? I've seen this error quite a few times recently, without ever seeing it in the past, and would wager that it's related to completed files being removed, perhaps in conjunction with unwanted files. In my case, a Force Recheck seems to have resolved it.

[Cyno01]

This is possibly not the cause of the error in every instance, but i think its running into a file name and path length limit thing. I havent tested to the exact digit, but is at least lower than windows file name/path length limit. Ive had good luck fixing it by going in and shortening file and folder names and then they work fine again after a recheck. For me at least this only seems to be happening to torrents with a lot of very long named subfolders or that go several subfolders deep, and my fix has been 100% so far out of a half dozen or so ive had problems with so far.

[oplex]

This is most likely an issue were the drive is overloaded. This might indicate that the drive that hosts the torrents needs to be reformatted or switched out due to failing hardware.

[isochronous]

@insurw please don't post huge text dumps, debug logs, etc. directly into the issue thread. If you need to post a large amount of text create a pastebin and post the link.

[lagaydude]

I have solved this issue quite simply after struggling with it on more than 20 occasions. The problem has ALWAYS been that the destination drive, internal or external, was too full to fit the full size of the torrent. Insufficient storage has been the culprit every time.

Once I free up space on the destination drive by transferring files to a new drive or deleting - and restart qBittorrent or the entire comp - the torrents resume and the I/O error notifications cease.

I usually leach 4 torrents simultaneously, so I do not know if the errors begin once a single torrent file is larger than the available space, or if the total needed space for multiple torrents is larger than what is available. This has been the problem regardless of if I have the 'pre-allocate space for torrent files' option on or off.

Hope that helps!

[millionsknives]

I was getting this problem on my Macbook while trying to download a large file to an external hard drive. I did two things which fixed it:

1: Select the hard drive > Get info > Sharing & Permissions > make sure 'everyone' is set to read & write (click the lock below to alter the settings)
2: In Qbittorrent > preferences > downloads > tick pre-allocate disk space for all files

[WoobeeAU]

On my Win 10 system, I found that switching from SSD to a mechanical drive as destination for downloads was an effective workaround to avoid the I/O errors. I hope this helps someone!

[draos]

My experience with this annoying bug:

It happens only with some specific torrents, of various sizes.
The error message is usually incomplete, with "reason" part that should come after filename clipped.
Destination disks are healthy, and I turned the file pre-allocation on.
Moving the destination or rebooting does not help, neither did stop-zip-delete-unzip-recheck cycle.
I/O error is reported on specific files, even when they are marked as "don't download" after the first occurrence of the error.
I had an impression that file paths might be too long (why do torrent creators do that? ), so I moved destination to the root of the disk - didn't help. Again, particularly annoying is that the error pops up on files even after I marked them as "don't download".

The version of the program is 3.1.9.2, running on Win7 Pro SP1

Any advice would be appreciated.

Update: I tried downloading with aria2c - it shows
Exception: [AbstractDiskWriter.cc:206] errNum=3 errorCode=16 Failed to open the file [a 275 chars log path from within the torrent] cause: The system cannot find the path specified.

So, it seems that the culprit really is too long pathnames.

So:

• Is it possible to make the program really ignore the files set to "not downloaded" ?
• Is it possible to ignore I/O errors instead of pausing the torrent?
• Is there any chance that future versions of qB will use Unicode very long filenames on Windows?

Thanks!

[sledgehammer999]

The version of the program is 3.1.9.2, running on Win7 Pro SP1

Any advice would be appreciated.

Maybe start with using latest version aka 4.0.3. Your version is ancient.

[draos]

The version of the program is 3.1.9.2, running on Win7 Pro SP1

Any advice would be appreciated.

Maybe start with using latest version aka 4.0.3. Your version is ancient.

Ah, I get it - my 3.1.9.2 says "no more recent versions available _on Sourceforge_" - you have migrated to github. I will try, but I am not holding my breath...

Thanks!

[rsn8887]

Same bug here, how has this not been fixed in three years?

[draos]

I found out what that was - too long pathnames.

Windows do have an alternate API allowing for long pathnames, but
apparently torrent clients don't use it (perhaps because on Linux that's
not a problem), don't attempt to report the error accurately, and don't
allow for filename manipulation withing the collection being leeched.

On 24 March 2018 at 21:28, rsn8887 [e-mail] wrote:

Same bug here, how has this not been fixed?

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[arvidn]

@rsn8887 I'm pretty sure all the known causes of IOErrors have been fixed. In order to fix the error you're encountering, please provide more information. Such as, the specific operation that fails and the full error message.

@draos libtorrent does use UNC paths (when configured to), in order to support long filenames.

[Nordomus]

Ehhh 5 years and still errors, screw that.

[draos]

Very well - how to configure it properly? I didn't find appropriate option
in qbtorrent settings.

I am rather sure that long pathnames were indeed the problem - all torrents
displaying I/O error had files with pathnames longer than 255 chars, and no
disk diagnostics I tried showed any problem with it. With one or two
torrents my destination folder was to blame - it was "too deep", and moving
the destination to the root of the destination drive solved the problem.
But, others had paths over the limit withing the torrent.

I guess that the workaround on Windows 10 will be to run some command-line
client within Ubuntu subsystem, but for those (like me) still on Win 7 - no
luck!

On 24 March 2018 at 22:59, Arvid Norberg [e-mail] wrote:

@draos https://github.com/draos libtorrent does use UNC paths (when
configured to), in order to support long filenames.

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[RoseTheFlower]

I've been getting the same kind of errors for a few months on Windows 10. It affects torrents where some files aren't checked for downloading, while the rest are finished and the overall progress is thus at 100%.

[token0]

Same sh*t. W7 x64, 48 GB RAM. Version 4.1.1.

[draos]

Again, this proved to be "filenames too long" problem. Those torrents work
fine on Linux, but I am not sure will they on Ubuntu subsystem on Win10 - a
thing to test.

On 19 June 2018 at 21:59, token0 [e-mail] wrote:

Same sh*t. W7 x64, 48 GB RAM. Version 4.1.1.

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[rsn8887]

I found out my IO errors were most probably due to a drive that was beginning to fail. After a while the hard disc drive failed completely.

With my new hard disc, I haven't experienced any IO errors yet. But I haven't downloaded much either...

[vtolkach]

This bug drives me crazy. I/O error appears foe even for previously downloaded but deleted (and marked not to download) files. Filenames are not too long. Average size of downloaded files 300-400Mb; Using external hard disk, Win10 x64, qbittorrent 4.1.1.
The most annoying thing is that after this error downloading stops and you have to stop/start it again manually.

[arvidn]

another cause of these errors have been fixed in the libtorrent 1.1.x branch (RC_1_1). Specifically when using a part file

[CatPlanet]

Win 7, qbittorrent 4.1.1 with brand new HDD, files around 350Mb, same issue. It's annoying as all f*cks.

[Iistros]

Seems it's an issue with the latest release qBittorrent 4.1.1
Was getting this error on every torrent right after updating, reverting to 4.0.4 and everything is fine.

[realtw]

Getting this with 4.1.1, torrent around 300 GB, avg file size 1GB. Checked all disks, no SMART errors. Both on SSD and HDD

[Dyalibya]

I'm getting this error again on Windows 8.1, Qbt 4.1.1 , 22 GB torrent with 600 MB files
Tried deleting and restarting the torrent with no result, I just disabled the files that cause the error

[Raitsa]

I started having these I/O errors when I left Windows10 and went for Linux (Solus).

Trying to download torrents and this happens with some torrents, they are a hit & miss, about 50% fail with no apparent logic.
Sometimes deleting and redownloading can help dl the torrent 100% but sometimes not.
NAS is all healthy, never had any probs with it.

v4.1.2 did not solve this, same prob still.

(N) 2018-08-07T18:36:32 - qBittorrent v4.1.1 started
(I) 2018-08-07T18:36:32 - qBittorrent is trying to listen on any interface port: 8999
(N) 2018-08-07T18:36:32 - Peer ID: -qB4110-
(N) 2018-08-07T18:36:32 - HTTP User-Agent is 'qBittorrent/4.1.1'
(I) 2018-08-07T18:36:32 - DHT support [ON]
(I) 2018-08-07T18:36:32 - Local Peer Discovery support [ON]
(I) 2018-08-07T18:36:32 - PeX support [ON]
(I) 2018-08-07T18:36:32 - Anonymous mode [OFF]
(I) 2018-08-07T18:36:32 - Encryption support [ON]
(I) 2018-08-07T18:36:32 - Embedded Tracker [OFF]
(I) 2018-08-07T18:36:32 - UPnP / NAT-PMP support [ON]
(I) 2018-08-07T18:36:32 - GeoIP database loaded. Type: GeoLite2-Country. Build time: Wed Jul 4 00:23:33 2018.
(N) 2018-08-07T18:36:33 - Options were saved successfully.
(I) 2018-08-07T18:36:33 - qBittorrent is successfully listening on interface :: port: TCP/8999
(I) 2018-08-07T18:36:33 - qBittorrent is successfully listening on interface 0.0.0.0 port: TCP/8999
(I) 2018-08-07T18:36:33 - qBittorrent is successfully listening on interface 0.0.0.0 port: UDP/8999
(I) 2018-08-07T18:36:33 - External IP: 85.76.....
(N) 2018-08-07T18:36:33 - Download first and last piece first: Off, torrent: 'Solus-3-Budgie.iso'
(N) 2018-08-07T18:36:33 - 'Solus-3-Budgie.iso' added to download list.
(N) 2018-08-07T18:36:36 - An I/O error occurred, 'Solus-3-Budgie.iso' paused. Solus-3-Budgie.iso fallocate (/run/user/1000/gvfs/smb-share:server=nas.local,share=downloads/Solus-3-Budgie.iso) error: Operation not supported

[arvidn]

@Raitsa it looks like the drive you're saving to does not support pre-allocating space for files. you may want to try using sparse-mode instead.

[Raitsa]

Thanks for the reply @arvidn

No matter what I try, same thing keeps happening.
Pre-allocating is off.
Have tried changing settings now quite a few ways, no help.
I have tried with Deluge & Transmission too, same thing happens with em.

Today managed to dl 3.4Gib file called Outpost, the others not.

(N) 2018-08-19T12:59:45 - qBittorrent v4.1.2 started
(N) 2018-08-19T12:59:45 - 'The.Investigator.A.British.Crime.Story.S02E02.XviD-AFG' added to download list.
(N) 2018-08-19T13:10:47 - An I/O error occurred, 'www.Torrenting.com - The.Investigator.A.British.Crime.Story.S02E02.XviD-AFG' paused. www.Torrenting.com - The.Investigator.A.British.Crime.Story.S02E02.XviD-AFG open (/run/user/1000/gvfs/smb-share:server=192.168.0.120,share=ladatut/www.Torrenting.com - The.Investigator.A.British.Crime.Story.S02E02.XviD-AFG/The.Investigator.A.British.Crime.Story.S02E02.XviD-AFG.avi) error: Operation not supported
(N) 2018-08-19T13:13:07 - 'www.Torrenting.com - The.Investigator.A.British.Crime.Story.S02E02.XviD-AFG' was removed from the transfer list and hard disk.
(N) 2018-08-19T19:58:26 - qBittorrent v4.1.2 started
(N) 2018-08-19T19:58:26 - Download first and last piece first: Off, torrent: 'Year.Million.S01.720p.WEB-DL.DD5.1.H.264-NTb'
(N) 2018-08-19T19:58:26 - 'Year.Million.S01.720p.WEB-DL.DD5.1.H.264-NTb' added to download list.
(N) 2018-08-19T19:59:01 - 'www.Torrenting.com - The.Investigator.A.British.Crime.Story.S02E01.XviD-AFG' was removed from the transfer list.
(N) 2018-08-19T20:25:04 - qBittorrent v4.1.2 started
(N) 2018-08-19T20:25:04 - Download first and last piece first: Off, torrent: 'Outpost Trilogy HD 720 FinSub'
(N) 2018-08-19T20:25:04 - 'Outpost Trilogy HD 720 FinSub' added to download list.
(N) 2018-08-19T21:07:48 - An I/O error occurred, 'Year.Million.S01.720p.WEB-DL.DD5.1.H.264-NTb' paused. Year.Million.S01.720p.WEB-DL.DD5.1.H.264-NTb open (/run/user/1000/gvfs/smb-share:server=192.168.0.120,share=ladatut/Year.Million.S01.720p.WEB-DL.DD5.1.H.264-NTb/Year.Million.S01E06.Beyond.the.Cosmos.720p.WEB-DL.DD5.1.H.264-NTb.mkv) error: Operation not supported

[arvidn]

please test this patch! https://github.com/arvidn/libtorrent/pull/3257

[LuckySandwich]

I think this bug is related to https://bugzilla.gnome.org/show_bug.cgi?id=748106#c6

Further reading https://bugzilla.gnome.org/show_bug.cgi?id=777152#c3

[arvidn]

indeed. @Raitsa s problem is explained by that bugreport. I must say it's quite broken if you can't update a file, but only append or replace it.

The only problem is that this bug report does not belong in this ticket, as it has since long been fixed. @sledgehammer999 what do you think about closing it?

[Uchiha-Jay]

I moved from windows to archlinux ,seems this bug occurred in both system.....
buffer i/o error on dev logical block lost sync page write

[Seluj78]

Same here, MacOs 10.14.1, constant I/O erros

[bavariancake]

For what it's worth, qBittorrent actually _alerted_ me to a kext (on a hackintosh) that was corrupting memory. I had a suspicion this was happening already, but thought this corruption would be manageable after bootup. qBittorrent was the only program with enough integrity checks to show that everything was not written as expected, and showed a warning dialog. Once I removed the offending kext, the issue disappeared.

qBittorrent is a great benchmark for a system due to the large number of small writes and reads - consider that you may have a kext or hardware issue, like I did. (Or hey, it may be qBittorrent, but I just wanted to add that this client might help you find the real problem!)

[Raitsa]

Hey guys, long time no hear and good to back with a very positive report:

no more errors downloading to a NAS (well its been one night only so far but all downloads successful so far).

MX Linux 18.3
Qbittorrent 4.1.6 64bit
A new NAS (Synology Diskstation 218+), the old one was a Thecus N7510.
Torrent downloads go to smb://nas/downloads/
Python-libtorrent 1.1.11-2-mx17+1

Yihaa!!

[Raitsa]

Correction: downloads succeed if there are straight up usable video files inside the archive (mkv avi mp4 TS etc).
Biggest download has been 116.42 GB which contained 8 different .mkv 2160p files, downloaded all ok.

If there are multiple rar files inside the archive, all downloads will result in an error and a stopped download in the first minute or so :-(

[FranciscoPombal]

The only problem is that this bug report does not belong in this ticket, as it has since long been fixed. @sledgehammer999 what do you think about closing it?