Timeshift: Canceled and removed backup still uses disk space

[williamfromtexas]

I originally commented that this is similar with bug #228, but that user did not report inability to recover the disk space.

In my case, it was the first time I ever used Timeshift. I had around 40gb of free space and ran a Timeshift snapshot of 39gb. (Actually I confused the size of the snapshot as a free space indication, which is why I proceeded.)

After about 10 minutes, while Timeshift was still running, the system gave me a 1gb remaining warning, so I cancelled it. After closing the dialogue window the cancelled snapshot did not appear in the app's GUI to delete, so I used the app's browse button to open the directory and deleted the new /timeshift/snapshot folder manually.

However, the space was not recovered, and I now seem to be missing 39gb. I tried searching the system for large folders but can't find it. I am guessing there is a temp file somewhere that I can't find.

Linux Mint 18.3, Timeshift 17.11, LUKS full disk

Attached is the log file, you can see at 17:03:29 the backup begins and I cancel it at 17:15.

[williamfromtexas]

Attachment didn't work, here is the paste:

[17:01:32] Session log file: /var/log/timeshift/2018-11-08_17-01-32_gui.log
[17:01:32] Distribution: LinuxMint 18.3 (sylvia)
[17:01:32] DIST_ID: LinuxMint
[17:01:32] Main: check_dependencies()
[17:01:32] Main: add_default_exclude_entries()
[17:01:32] Main: add_default_exclude_entries(): exit
[17:01:32] update_partitions()
[17:01:32] found link: /dev/mapper/sda5_crypt -> /dev/dm-0
[17:01:32] found link: /dev/mapper/mint--vg-root -> /dev/dm-1
[17:01:32] found link: /dev/mapper/mint--vg-swap_1 -> /dev/dm-2
[17:01:32]
[17:01:32] device ,pkname ,kname ,uuid ,mapped_name
[17:01:32] ----------------------------------------------------------------------------------------------------
[17:01:32] /dev/sda , ,sda , ,
[17:01:32] /dev/sda1 ,sda ,sda1 ,94fbfaaa-9721-4b71-8c2a-e62aa3546113 ,
[17:01:32] /dev/sda2 ,sda ,sda2 , ,
[17:01:32] /dev/sda5 ,sda ,sda5 ,bbcfaa31-a4c6-466b-94f7-993da219f85a ,
[17:01:32] /dev/dm-0 ,sda5 ,dm-0 ,VSBxMt-GGqh-xZ7h-Z2xq-pFDl-EqCV-5DnpD1 ,sda5_crypt
[17:01:32] /dev/dm-1 ,dm-0 ,dm-1 ,962f3c4d-67f3-4bc0-afd1-57189ffe087c ,mint--vg-root
[17:01:32] /dev/dm-2 ,dm-0 ,dm-2 ,734129c7-35ee-4df7-a329-e946664d5342 ,mint--vg-swap_1
[17:01:32] /dev/sr0 , ,sr0 , ,
[17:01:32]
[17:01:32] Device: get_block_devices_using_lsblk(): 8
[17:01:32] Device: get_disk_space_using_df(): 2
[17:01:32] Device: get_mounted_filesystems_using_mtab(): 2
[17:01:32] Device: get_filesystems(): 8
[17:01:32] partition list updated
[17:01:32] detect_system_devices()
[17:01:32] /boot is mapped to device: /dev/sda1, UUID=94fbfaaa-9721-4b71-8c2a-e62aa3546113
[17:01:32] / is mapped to device: /dev/dm-1, UUID=962f3c4d-67f3-4bc0-afd1-57189ffe087c
[17:01:32] Searching subvolume for system at path: /
[17:01:32] Users: user root
[17:01:32] Encrypted home users:
[17:01:32] Encrypted home dirs:

[17:01:32] Encrypted private dirs:

[17:01:32] Main: load_app_config()
[17:01:32] First run mode (config file not found)
[17:01:32] Selected default snapshot type: RSYNC
[17:01:32] App config loaded: /etc/timeshift.json
[17:01:32] IconManager: init()
[17:01:32] bin_path: /usr/bin/timeshift-gtk
[17:01:32] found images directory: /usr/share/timeshift/images
[17:01:32] Main(): ok
[17:01:32] Main: initialize_repo()
[17:01:32] backup_uuid=
[17:01:32] backup_parent_uuid=
[17:01:32] try_select_default_device_for_backup()
[17:01:32] SnapshotRepo: available()
[17:01:32] device is null
[17:01:32] is_available: false
[17:01:32] update_partitions()
[17:01:32] found link: /dev/mapper/sda5_crypt -> /dev/dm-0
[17:01:32] found link: /dev/mapper/mint--vg-root -> /dev/dm-1
[17:01:32] found link: /dev/mapper/mint--vg-swap_1 -> /dev/dm-2
[17:01:32]
[17:01:32] device ,pkname ,kname ,uuid ,mapped_name
[17:01:32] ----------------------------------------------------------------------------------------------------
[17:01:32] /dev/sda , ,sda , ,
[17:01:32] /dev/sda1 ,sda ,sda1 ,94fbfaaa-9721-4b71-8c2a-e62aa3546113 ,
[17:01:32] /dev/sda2 ,sda ,sda2 , ,
[17:01:32] /dev/sda5 ,sda ,sda5 ,bbcfaa31-a4c6-466b-94f7-993da219f85a ,
[17:01:32] /dev/dm-0 ,sda5 ,dm-0 ,VSBxMt-GGqh-xZ7h-Z2xq-pFDl-EqCV-5DnpD1 ,sda5_crypt
[17:01:32] /dev/dm-1 ,dm-0 ,dm-1 ,962f3c4d-67f3-4bc0-afd1-57189ffe087c ,mint--vg-root
[17:01:32] /dev/dm-2 ,dm-0 ,dm-2 ,734129c7-35ee-4df7-a329-e946664d5342 ,mint--vg-swap_1
[17:01:32] /dev/sr0 , ,sr0 , ,
[17:01:32]
[17:01:32] Device: get_block_devices_using_lsblk(): 8
[17:01:32] Device: get_disk_space_using_df(): 2
[17:01:32] Device: get_mounted_filesystems_using_mtab(): 2
[17:01:32] Device: get_filesystems(): 8
[17:01:32] partition list updated
[17:01:32] SnapshotRepo: from_device(): RSYNC
[17:01:32] SnapshotRepo: init_from_device()
[17:01:32]
[17:01:32] SnapshotRepo: unlock_and_mount_devices()
[17:01:32] device=/dev/sda1
[17:01:32] SnapshotRepo: unlock_and_mount_device()
[17:01:32] device=/dev/sda1
[17:01:32] Device: get_mounted_filesystems_using_mtab(): 2
[17:01:32] SnapshotRepo: load_snapshots()
[17:01:32] SnapshotRepo: unlock_and_mount_device(): exit
[17:01:32] Selected snapshot device: /dev/sda1
[17:01:32] Free space: 83.4 MB
[17:01:32] SnapshotRepo: check_status()
[17:01:32] SnapshotRepo: available()
[17:01:32] is_available: ok
[17:01:32] SnapshotRepo: has_snapshots()
[17:01:32] SnapshotRepo: has_space()
[17:01:32] Device: get_disk_space_using_df(): 1
[17:01:32] no snapshots
[17:01:32] Snapshot device: '/dev/sda1'
[17:01:32] Snapshot location: /boot
[17:01:32] No snapshots on this device
[17:01:32] First snapshot requires: 0 B
[17:01:32] Status: NO_SNAPSHOTS_HAS_SPACE
[17:01:32]
[17:01:32] SnapshotRepo: check_status(): exit
[17:01:32] SnapshotRepo: init_from_device(): exit
[17:01:32] Selected default snapshot device: /dev/sda1
[17:01:32] Main: initialize_repo(): exit
[17:01:32] MainWindow: MainWindow()
[17:01:32] SnapshotListBox: SnapshotListBox()
[17:01:32] SnapshotListBox: SnapshotListBox(): exit
[17:01:32] MainWindow: MainWindow(): exit
[17:01:33] MainWindow(): init_delayed()
[17:01:33] SnapshotRepo: available()
[17:01:33] is_available: ok
[17:01:33] SnapshotRepo: available()
[17:01:33] is_available: ok
[17:01:33] SnapshotRepo: load_snapshots()
[17:01:33] SnapshotRepo: check_status()
[17:01:33] SnapshotRepo: available()
[17:01:33] is_available: ok
[17:01:33] SnapshotRepo: has_snapshots()
[17:01:33] SnapshotRepo: has_space()
[17:01:33] Device: get_disk_space_using_df(): 1
[17:01:33] no snapshots
[17:01:33] Snapshot device: '/dev/sda1'
[17:01:33] Snapshot location: /boot
[17:01:33] No snapshots on this device
[17:01:33] First snapshot requires: 0 B
[17:01:33] Status: NO_SNAPSHOTS_HAS_SPACE
[17:01:33]
[17:01:33] SnapshotRepo: check_status(): exit
[17:01:33] SnapshotRepo: has_snapshots()
[17:01:33] SnapshotRepo: has_snapshots()
[17:01:33] MainWindow: btn_wizard_clicked()
[17:01:33] SetupWizardWindow: SetupWizardWindow()
[17:01:33] Setting schedule_daily for first run
[17:01:33] SnapshotBackendBox: SnapshotBackendBox()
[17:01:33] SnapshotBackendBox: SnapshotBackendBox(): exit
[17:01:33] EstimateBox: EstimateBox()
[17:01:33] EstimateBox: EstimateBox(): exit
[17:01:33] BackupDeviceBox: BackupDeviceBox()
[17:01:33] BackupDeviceBox: BackupDeviceBox(): exit
[17:01:33] ScheduleBox: ScheduleBox()
[17:01:33] ScheduleBox: ScheduleBox(): exit
[17:01:33] FinishBox: FinishBox()
[17:01:33] FinishBox: FinishBox(): exit
[17:01:33] SetupWizardWindow: SetupWizardWindow(): exit
[17:01:33] MainWindow(): init_delayed(): exit
[17:01:33]
[17:01:33] page: 0
[17:01:36] try_select_default_device_for_backup()
[17:01:36] SnapshotRepo: available()
[17:01:36] is_available: ok
[17:01:44]
[17:01:44] page: 1
[17:01:44] EstimateBox: thread started
[17:01:44] estimate_system_size()
[17:01:44] Using temp dir '/tmp/timeshift/QZPezVSR'
[17:01:44] Main: save_exclude_list_for_backup()
[17:01:44] Main: create_exclude_list_for_backup()
[17:01:44] Main: create_exclude_list_for_backup(): exit
[17:01:44] LC_ALL=C ; rsync -ai --delete --numeric-ids --relative --stats --dry-run --delete-excluded --exclude-from='/tmp/timeshift/QZPezVSR/exclude.list' /. '/tmp/timeshift/QZPezVSR/empty' &> '/tmp/timeshift/QZPezVSR/rsync.log'
[17:02:15] First snapshot size: 39.7 GB
[17:02:15] File count: 861153
[17:02:15] Main: save_app_config()
[17:02:15] SnapshotRepo: available()
[17:02:15] is_available: ok
[17:02:15] App config saved: /etc/timeshift.json
[17:02:15] estimate_system_size(): ok
[17:02:15] EstimateBox: thread finished
[17:02:15]
[17:02:15] page: 2
[17:02:15] update_partitions()
[17:02:16] found link: /dev/mapper/sda5_crypt -> /dev/dm-0
[17:02:16] found link: /dev/mapper/mint--vg-root -> /dev/dm-1
[17:02:16] found link: /dev/mapper/mint--vg-swap_1 -> /dev/dm-2
[17:02:16]
[17:02:16] device ,pkname ,kname ,uuid ,mapped_name
[17:02:16] ----------------------------------------------------------------------------------------------------
[17:02:16] /dev/sda , ,sda , ,
[17:02:16] /dev/sda1 ,sda ,sda1 ,94fbfaaa-9721-4b71-8c2a-e62aa3546113 ,
[17:02:16] /dev/sda2 ,sda ,sda2 , ,
[17:02:16] /dev/sda5 ,sda ,sda5 ,bbcfaa31-a4c6-466b-94f7-993da219f85a ,
[17:02:16] /dev/dm-0 ,sda5 ,dm-0 ,VSBxMt-GGqh-xZ7h-Z2xq-pFDl-EqCV-5DnpD1 ,sda5_crypt
[17:02:16] /dev/dm-1 ,dm-0 ,dm-1 ,962f3c4d-67f3-4bc0-afd1-57189ffe087c ,mint--vg-root
[17:02:16] /dev/dm-2 ,dm-0 ,dm-2 ,734129c7-35ee-4df7-a329-e946664d5342 ,mint--vg-swap_1
[17:02:16] /dev/sr0 , ,sr0 , ,
[17:02:16]
[17:02:16] Device: get_block_devices_using_lsblk(): 8
[17:02:16] Device: get_disk_space_using_df(): 2
[17:02:16] Device: get_mounted_filesystems_using_mtab(): 2
[17:02:16] Device: get_filesystems(): 8
[17:02:16] partition list updated
[17:02:16] SnapshotRepo: check_status()
[17:02:16] SnapshotRepo: available()
[17:02:16] is_available: ok
[17:02:16] SnapshotRepo: has_snapshots()
[17:02:16] SnapshotRepo: has_space()
[17:02:16] Device: get_disk_space_using_df(): 1
[17:02:16] no snapshots
[17:02:16] Snapshot device: '/dev/sda1'
[17:02:16] Snapshot location: /boot
[17:02:16] Not enough disk space (< 39.7 GB)
[17:02:16] Select another device or free up some space
[17:02:16] Status: NO_SNAPSHOTS_NO_SPACE
[17:02:16]
[17:02:16] SnapshotRepo: check_status(): exit
[17:03:07]
[17:03:07] page: 0
[17:03:10]
[17:03:10] page: 1
[17:03:10] EstimateBox: size > 0
[17:03:10]
[17:03:10] page: 2
[17:03:10] update_partitions()
[17:03:10] found link: /dev/mapper/sda5_crypt -> /dev/dm-0
[17:03:10] found link: /dev/mapper/mint--vg-root -> /dev/dm-1
[17:03:10] found link: /dev/mapper/mint--vg-swap_1 -> /dev/dm-2
[17:03:10]
[17:03:10] device ,pkname ,kname ,uuid ,mapped_name
[17:03:10] ----------------------------------------------------------------------------------------------------
[17:03:10] /dev/sda , ,sda , ,
[17:03:10] /dev/sda1 ,sda ,sda1 ,94fbfaaa-9721-4b71-8c2a-e62aa3546113 ,
[17:03:10] /dev/sda2 ,sda ,sda2 , ,
[17:03:10] /dev/sda5 ,sda ,sda5 ,bbcfaa31-a4c6-466b-94f7-993da219f85a ,
[17:03:10] /dev/dm-0 ,sda5 ,dm-0 ,VSBxMt-GGqh-xZ7h-Z2xq-pFDl-EqCV-5DnpD1 ,sda5_crypt
[17:03:10] /dev/dm-1 ,dm-0 ,dm-1 ,962f3c4d-67f3-4bc0-afd1-57189ffe087c ,mint--vg-root
[17:03:10] /dev/dm-2 ,dm-0 ,dm-2 ,734129c7-35ee-4df7-a329-e946664d5342 ,mint--vg-swap_1
[17:03:10] /dev/sr0 , ,sr0 , ,
[17:03:10]
[17:03:10] Device: get_block_devices_using_lsblk(): 8
[17:03:10] Device: get_disk_space_using_df(): 2
[17:03:10] Device: get_mounted_filesystems_using_mtab(): 2
[17:03:10] Device: get_filesystems(): 8
[17:03:10] partition list updated
[17:03:10] SnapshotRepo: check_status()
[17:03:10] SnapshotRepo: available()
[17:03:10] is_available: ok
[17:03:10] SnapshotRepo: has_snapshots()
[17:03:10] SnapshotRepo: has_space()
[17:03:10] Device: get_disk_space_using_df(): 1
[17:03:10] no snapshots
[17:03:10] Snapshot device: '/dev/sda1'
[17:03:10] Snapshot location: /boot
[17:03:10] Not enough disk space (< 39.7 GB)
[17:03:10] Select another device or free up some space
[17:03:10] Status: NO_SNAPSHOTS_NO_SPACE
[17:03:10]
[17:03:10] SnapshotRepo: check_status(): exit
[17:03:17] try_change_device: /dev/sda
[17:03:18] try_change_device: /dev/dm-1
[17:03:18]

[17:03:18] selected device: /dev/dm-1
[17:03:18] fstype: ext4
[17:03:18] SnapshotRepo: from_device(): RSYNC
[17:03:18] SnapshotRepo: init_from_device()
[17:03:18]
[17:03:18] SnapshotRepo: unlock_and_mount_devices()
[17:03:18] device=/dev/dm-1
[17:03:18] SnapshotRepo: unlock_and_mount_device()
[17:03:18] device=/dev/dm-1
[17:03:18] Device: get_mounted_filesystems_using_mtab(): 2
[17:03:18] SnapshotRepo: load_snapshots()
[17:03:18] SnapshotRepo: unlock_and_mount_device(): exit
[17:03:18] Selected snapshot device: /dev/dm-1
[17:03:18] Free space: 48.9 GB
[17:03:18] SnapshotRepo: check_status()
[17:03:18] SnapshotRepo: available()
[17:03:18] is_available: ok
[17:03:18] SnapshotRepo: has_snapshots()
[17:03:18] SnapshotRepo: has_space()
[17:03:18] Device: get_disk_space_using_df(): 1
[17:03:18] no snapshots
[17:03:18] Snapshot device: '/dev/dm-1'
[17:03:18] Snapshot location: /
[17:03:18] No snapshots on this device
[17:03:18] First snapshot requires: 39.7 GB
[17:03:18] Status: NO_SNAPSHOTS_HAS_SPACE
[17:03:18]
[17:03:18] SnapshotRepo: check_status(): exit
[17:03:18] SnapshotRepo: init_from_device(): exit
[17:03:18] SnapshotRepo: check_status()
[17:03:18] SnapshotRepo: available()
[17:03:18] is_available: ok
[17:03:18] SnapshotRepo: has_snapshots()
[17:03:18] SnapshotRepo: has_space()
[17:03:18] Device: get_disk_space_using_df(): 1
[17:03:18] no snapshots
[17:03:18] Snapshot device: '/dev/dm-1'
[17:03:18] Snapshot location: /
[17:03:18] No snapshots on this device
[17:03:18] First snapshot requires: 39.7 GB
[17:03:18] Status: NO_SNAPSHOTS_HAS_SPACE
[17:03:18]
[17:03:18] SnapshotRepo: check_status(): exit
[17:03:23] try_change_device: /dev/sda1
[17:03:23]

[17:03:23] selected device: /dev/sda1
[17:03:23] fstype: ext2
[17:03:23] SnapshotRepo: from_device(): RSYNC
[17:03:23] SnapshotRepo: init_from_device()
[17:03:23]
[17:03:23] SnapshotRepo: unlock_and_mount_devices()
[17:03:23] device=/dev/sda1
[17:03:23] SnapshotRepo: unlock_and_mount_device()
[17:03:23] device=/dev/sda1
[17:03:23] Device: get_mounted_filesystems_using_mtab(): 2
[17:03:23] SnapshotRepo: load_snapshots()
[17:03:23] SnapshotRepo: unlock_and_mount_device(): exit
[17:03:23] Selected snapshot device: /dev/sda1
[17:03:23] Free space: 83.4 MB
[17:03:23] SnapshotRepo: check_status()
[17:03:23] SnapshotRepo: available()
[17:03:23] is_available: ok
[17:03:23] SnapshotRepo: has_snapshots()
[17:03:23] SnapshotRepo: has_space()
[17:03:23] Device: get_disk_space_using_df(): 1
[17:03:23] no snapshots
[17:03:23] Snapshot device: '/dev/sda1'
[17:03:23] Snapshot location: /boot
[17:03:23] Not enough disk space (< 39.7 GB)
[17:03:23] Select another device or free up some space
[17:03:23] Status: NO_SNAPSHOTS_NO_SPACE
[17:03:23]
[17:03:23] SnapshotRepo: check_status(): exit
[17:03:23] SnapshotRepo: init_from_device(): exit
[17:03:23] SnapshotRepo: check_status()
[17:03:23] SnapshotRepo: available()
[17:03:23] is_available: ok
[17:03:23] SnapshotRepo: has_snapshots()
[17:03:23] SnapshotRepo: has_space()
[17:03:23] Device: get_disk_space_using_df(): 1
[17:03:23] no snapshots
[17:03:23] Snapshot device: '/dev/sda1'
[17:03:23] Snapshot location: /boot
[17:03:23] Not enough disk space (< 39.7 GB)
[17:03:23] Select another device or free up some space
[17:03:23] Status: NO_SNAPSHOTS_NO_SPACE
[17:03:23]
[17:03:23] SnapshotRepo: check_status(): exit
[17:03:29] try_change_device: /dev/dm-1
[17:03:29]

[17:03:29] selected device: /dev/dm-1
[17:03:29] fstype: ext4
[17:03:29] SnapshotRepo: from_device(): RSYNC
[17:03:29] SnapshotRepo: init_from_device()
[17:03:29]
[17:03:29] SnapshotRepo: unlock_and_mount_devices()
[17:03:29] device=/dev/dm-1
[17:03:29] SnapshotRepo: unlock_and_mount_device()
[17:03:29] device=/dev/dm-1
[17:03:29] Device: get_mounted_filesystems_using_mtab(): 2
[17:03:29] SnapshotRepo: load_snapshots()
[17:03:29] SnapshotRepo: unlock_and_mount_device(): exit
[17:03:29] Selected snapshot device: /dev/dm-1
[17:03:29] Free space: 48.9 GB
[17:03:29] SnapshotRepo: check_status()
[17:03:29] SnapshotRepo: available()
[17:03:29] is_available: ok
[17:03:29] SnapshotRepo: has_snapshots()
[17:03:29] SnapshotRepo: has_space()
[17:03:29] Device: get_disk_space_using_df(): 1
[17:03:29] no snapshots
[17:03:29] Snapshot device: '/dev/dm-1'
[17:03:29] Snapshot location: /
[17:03:29] No snapshots on this device
[17:03:29] First snapshot requires: 39.7 GB
[17:03:29] Status: NO_SNAPSHOTS_HAS_SPACE
[17:03:29]
[17:03:29] SnapshotRepo: check_status(): exit
[17:03:29] SnapshotRepo: init_from_device(): exit
[17:03:29] SnapshotRepo: check_status()
[17:03:29] SnapshotRepo: available()
[17:03:29] is_available: ok
[17:03:29] SnapshotRepo: has_snapshots()
[17:03:29] SnapshotRepo: has_space()
[17:03:29] Device: get_disk_space_using_df(): 1
[17:03:29] no snapshots
[17:03:29] Snapshot device: '/dev/dm-1'
[17:03:29] Snapshot location: /
[17:03:29] No snapshots on this device
[17:03:29] First snapshot requires: 39.7 GB
[17:03:29] Status: NO_SNAPSHOTS_HAS_SPACE
[17:03:29]
[17:03:29] SnapshotRepo: check_status(): exit
[17:03:32] crontab -l
[17:03:32] Failed to read cron tab
[17:03:32] crontab -l
[17:03:32] Failed to read cron tab
[17:03:32] Added cron task: /etc/cron.d/timeshift-hourly
[17:03:32] Main: save_app_config()
[17:03:32] SnapshotRepo: available()
[17:03:32] is_available: ok
[17:03:32] App config saved: /etc/timeshift.json
[17:03:32] SnapshotRepo: load_snapshots()
[17:03:32] SnapshotRepo: available()
[17:03:32] is_available: ok
[17:03:32] SnapshotRepo: load_snapshots()
[17:03:32] SnapshotRepo: check_status()
[17:03:32] SnapshotRepo: available()
[17:03:32] is_available: ok
[17:03:32] SnapshotRepo: has_snapshots()
[17:03:32] SnapshotRepo: has_space()
[17:03:32] Device: get_disk_space_using_df(): 1
[17:03:32] no snapshots
[17:03:32] Snapshot device: '/dev/dm-1'
[17:03:32] Snapshot location: /
[17:03:32] No snapshots on this device
[17:03:32] First snapshot requires: 39.7 GB
[17:03:32] Status: NO_SNAPSHOTS_HAS_SPACE
[17:03:32]
[17:03:32] SnapshotRepo: check_status(): exit
[17:03:32] SnapshotRepo: has_snapshots()
[17:03:32] SnapshotRepo: has_snapshots()
[17:03:40] SnapshotRepo: available()
[17:03:40] is_available: ok
[17:03:40] SnapshotRepo: has_space()
[17:03:40] Device: get_disk_space_using_df(): 1
[17:03:40] no snapshots
[17:03:40] BackupWindow: BackupWindow()
[17:03:40] EstimateBox: EstimateBox()
[17:03:40] EstimateBox: EstimateBox(): exit
[17:03:40] BackupDeviceBox: BackupDeviceBox()
[17:03:40] BackupDeviceBox: BackupDeviceBox(): exit
[17:03:40] BackupBox: BackupBox()
[17:03:40] BackupBox: BackupBox(): exit
[17:03:40] BackupFinishBox: BackupFinishBox()
[17:03:40] BackupFinishBox: BackupFinishBox(): exit
[17:03:40] BackupWindow: BackupWindow(): exit
[17:03:40] SnapshotRepo: available()
[17:03:40] is_available: ok
[17:03:40] SnapshotRepo: has_space()
[17:03:40] Device: get_disk_space_using_df(): 1
[17:03:40] no snapshots
[17:03:40]
[17:03:40] page: 2
[17:03:40] Main: create_snapshot()
[17:03:40] SnapshotRepo: has_space()
[17:03:40] Device: get_disk_space_using_df(): 1
[17:03:40] no snapshots
[17:03:40] mkdir: /timeshift/snapshots
[17:03:40] Main: backup_and_rotate()
[17:03:40] SnapshotRepo: available()
[17:03:40] is_available: ok
[17:03:40] SnapshotRepo: has_space()
[17:03:40] Device: get_disk_space_using_df(): 1
[17:03:40] no snapshots
[17:03:40] ------------------------------------------------------------------------------
[17:03:40] Creating new snapshot...(RSYNC)
[17:03:40] Saving to device: /dev/dm-1, mounted at path: /
[17:03:40] Main: save_exclude_list_for_backup()
[17:03:40] Main: create_exclude_list_for_backup()
[17:03:40] Main: create_exclude_list_for_backup(): exit
[17:03:40] Synching files with rsync...
[17:03:40] RsyncTask:execute()
[17:03:40] rsync -aii --recursive --verbose --delete --force --stats --delete-excluded --log-file='/timeshift/snapshots/2018-11-08_17-03-40/rsync-log' --exclude-from='/timeshift/snapshots/2018-11-08_17-03-40/exclude.list' --delete-excluded '/' '/timeshift/snapshots/2018-11-08_17-03-40/localhost/'
[17:03:40] RsyncTask:prepare(): saved: /tmp/timeshift/QZPezVSR/2018-08-11_17-03-40/script.sh
[17:03:40] AsyncTask: child_pid: 19563
[17:15:28] process_quit: 19563
[17:15:28] SnapshotRepo: available()
[17:15:28] is_available: ok
[17:15:28] SnapshotRepo: load_snapshots()
[17:15:28] loading snapshots from '/timeshift/snapshots': 0 found
[17:15:28] SnapshotRepo: check_status()
[17:15:28] SnapshotRepo: available()
[17:15:28] is_available: ok
[17:15:28] SnapshotRepo: has_snapshots()
[17:15:28] SnapshotRepo: has_space()
[17:15:28] Device: get_disk_space_using_df(): 1
[17:15:28] no snapshots
[17:15:28] Snapshot device: '/dev/dm-1'
[17:15:28] Snapshot location: /
[17:15:28] Not enough disk space (< 39.7 GB)
[17:15:28] Select another device or free up some space
[17:15:28] Status: NO_SNAPSHOTS_NO_SPACE
[17:15:28]
[17:15:28] SnapshotRepo: check_status(): exit
[17:15:28] SnapshotRepo: has_snapshots()
[17:15:29] E: rsync returned an error
[17:15:29] E: Failed to create new snapshot
[17:15:29] Failed to create snapshot
[17:15:29] AsyncTask: finish(): enter
[17:15:29] exit_code: -1
[17:15:29] ------------------------------------------------------------------------------
[17:15:29] SnapshotRepo: load_snapshots()
[17:15:29] loading snapshots from '/timeshift/snapshots': 0 found
[17:15:29] Symlinks updated
[17:16:45] main window: delete_selected()
[17:16:45] SnapshotRepo: available()
[17:16:45] is_available: ok
[17:16:45] SnapshotRepo: has_snapshots()
[17:16:50] SnapshotRepo: available()
[17:16:50] is_available: ok
[17:16:50] SnapshotRepo: has_space()
[17:16:50] Device: get_disk_space_using_df(): 1
[17:16:50] no snapshots
[17:16:52] exit_app()
[17:16:52] Main: save_app_config()
[17:16:52] SnapshotRepo: available()
[17:16:52] is_available: ok
[17:16:52] App config saved: /etc/timeshift.json
[17:16:52] crontab -l
[17:16:52] Failed to read cron tab
[17:16:52] crontab -l
[17:16:52] Failed to read cron tab
[17:16:52] Cron task exists: /etc/cron.d/timeshift-hourly
[17:16:52] unmount_target_device()
[17:16:52] clean_logs()

[williamfromtexas]

OK, I figured it out. The deleted partial snapshot wasn't in my user trash, it was in the root trash at /root/.local/share/Trash/

However, using the file manager to delete this only bounced the 39gb folder to my user trash -- and when I deleted from there, back to root trash! The solution was
sudo rm -rf /root/.local/share/Trash