Qbittorrent: Re-checking torrents failing and torrents downloading again / Corrupting files

Created on 5 Dec 2017  ·  3Comments  ·  Source: qbittorrent/qBittorrent

qBittorrent version and Operating System

v4.0.2 (64bit) / Windows 8.1

What is the problem

Checking completed torrent results in large amounts of the torrent being found to be incomplete. Sometimes re-checking will then find it to be complete, but re-checking again is just as likely to find it incomplete again.

This process is corrupting already downloaded torrents if a re-check is run, or if re-check on completion is set, it goes into a loop and continues to corrupt the download.

What is the expected behavior

A completed torrent should check as complete and not get corrupted.

Steps to reproduce

Re-check completed torrents.
Torrent checking stops at (for example) 58%.
Torrent begins to download again from 58%.
re-check torrent again.
Torrent check now completes to 100%
Torrent is moved to completed folder
Torrent re-checks automatically (I have that option enabled)
Re-check stops at 52% (or some other random value, but usually close to the previous value).
Torrent is moved back to incomplete folder
Torrent starts downloading
< process repeats >

Extra info(if any)

The point at which the rechecking fails seems to be random
The files which are marked as incomplete seem to be random (but seems the first file in a folder is more likely to fail)
It may only happen on Torrents where some files were marked to not download
Completed torrents are set to move to a different folder.
Re-check torrent when complete is enabled.
Some torrents were started with earlier versions of qBittorrent and qBittorrent has been upgraded since. I can't confirm if all problematic torrents were initially started with earlier versions.
Torrents are downloaded to a network share
The drive the network share is on is deduplicated. As such, size of file and size on disk are unrelated. This should not matter and I think is hidden via SMB anyway but seemed worth mentioning.

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picture ned-martin
👍3

Most helpful comment

Yeah... this bug is actually corrupting data. If anyone has not copied their completed torrents elsewhere, they will lose potentially huge amounts of data from this. Fortunately I had already copied most of the data I needed elsewhere, but this has corrupted / deleted a reasonable amount of data, including from some torrents which no longer have seeds, which it is now busy trying to download

I think that probably makes it a high priority.

I still can't replicate it in an way I can explain... but a few things I've noticed:

  • The various paths used by the system have different amounts of slashes on the end, sometimes it's two... which causes errors
  • It appears to have something to do with paths, and/or auto-moving when complete/storing incomplete torrents in a different folder
  • I managed to "fix" (stop them from always failing rechecking) some torrents by various combinations of manually setting their location / turning on or off "store incomplete torrents in..." but unfortunately can't tell you exactly what fixed them, and others are not yet fixed
picture ned-martin on 5 Dec 2017
👍2

All 3 comments

every single one of my 'finished' torrents that had been completed but marked errored started to redownload. 4000 torrents in my queue after upgrading. There were 20 before. Please god have mercy on me.

when i started to delete the new-old downloads and rebooted everything started downloading again. i'm not long for this world

mel-moth picture mel-moth on 5 Dec 2017
😄1

Yeah... this bug is actually corrupting data. If anyone has not copied their completed torrents elsewhere, they will lose potentially huge amounts of data from this. Fortunately I had already copied most of the data I needed elsewhere, but this has corrupted / deleted a reasonable amount of data, including from some torrents which no longer have seeds, which it is now busy trying to download

I think that probably makes it a high priority.

I still can't replicate it in an way I can explain... but a few things I've noticed:

  • The various paths used by the system have different amounts of slashes on the end, sometimes it's two... which causes errors
  • It appears to have something to do with paths, and/or auto-moving when complete/storing incomplete torrents in a different folder
  • I managed to "fix" (stop them from always failing rechecking) some torrents by various combinations of manually setting their location / turning on or off "store incomplete torrents in..." but unfortunately can't tell you exactly what fixed them, and others are not yet fixed
ned-martin picture ned-martin on 5 Dec 2017
👍2

Same here... I have like 60+ torrent rechecking at every startup for no reason
I delete them from QBT as soon as they are finished so this must prevent them from bugging again

But sometimes I suspect them to reappear back in QBT and so I DL them again without noticing, not sure (sometimes yes sometimes no)

zpoison picture zpoison on 14 Dec 2017
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