Core: Error response from daemon: Dockerfile parse error line 1: unknown instruction: ��F R O M

[brennfoster]

Problem encountered on https://dotnet.microsoft.com/learn/web/aspnet-microservice-tutorial/docker-image
Operating System: windows

Getting this error: "Error response from daemon: Dockerfile parse error line 1: unknown instruction: ��F R O M" when attempting to run this command: "docker build -t microservice ."

[karelz]

@leecow who can help troubleshoot Docker problems? This one seems general - maybe corrupted Docker install?

[gortok]

@brennfoster I copy and pasted the Dockerfile into a hex editor and didn't see those characters in the beginning. What did you copy the sample dockerfile into? It's possible it left in a BOM or some other artifact when you copied the text. Can you upload your sample repo and link us to it?

[gortok]

To resolve your issue, I'd open the dockerfile into a text editor capable of showing it in hex (I use notepad++ with HexEditor plugin); and manually removing those non characters. The first hex addresses you should see are 46 52:

[leecow]

@karelz - the illegal characters snuck in during the OP's copy/paste when creating the Dockerfile. Clean those out and it should build fine.

[karelz]

OK, seems to be user error. Closing. Let us know if that is not the case.

[brennfoster]

Sorry for not getting back to this sooner.

I typed out the content found here: https://dotnet.microsoft.com/learn/web/aspnet-microservice-tutorial/docker-file into the dockerfile and I'm still getting this error. I did this using VS Code and again using Notepad++. I shouldn't have inserted any illegal characters doing this.

[gortok]

You're definitely getting a byte-order mark being put into that file. You need to check the encoding of the file in Notepad++ and make sure "Encode in UTF-8 with BOM" is not selected. I would change the encoding of the file to "ANSI" and try again. I copied the same code and typed it in manually and did not get a byte-order mark, so it's likely to be a setting on your PC that's doing this (I have no knowledge of what such a setting would be).

[brennfoster]

Okay, switching encoding to "ANSI" worked. Thank you!

[KhadayatShailendra]

You're definitely getting a byte-order mark being put into that file. You need to check the encoding of the file in Notepad++ and make sure "Encode in UTF-8 with BOM" is not selected. I would change the encoding of the file to "ANSI" and try again. I copied the same code and typed it in manually and did not get a byte-order mark, so it's likely to be a setting on your PC that's doing this (I have no knowledge of what such a setting would be).

Thanks @gortok changing encoding in notepad++ to ANSI worked for me.

[srinivasjuluri1224]

Problem encountered on https://dotnet.microsoft.com/learn/web/aspnet-microservice-tutorial/docker-image
Operating System: windows

Getting this error: "Error response from daemon: Dockerfile parse error line 1: unknown instruction: ��F R O M" when attempting to run this command: "docker build -t microservice ."

perfect its working now