qBittorrent & operating system versions
qBittorrent: 5.2.3 (downloaded from official website)
OS: Windows 11 x64
Qt: 6.10.3
libtorrent-rasterbar: 1.2.20.0
What is the problem?
I found what appears to be a false "mismatching file size" error during fast resume validation.
The issue is reproducible with a specific filename. The file contents are valid and unchanged, but qBittorrent refuses to resume the torrent and reports:
22/08/2026 01:01 - Failed to restore torrent. Files were probably moved or storage isn't accessible.
Torrent: "Sega - Mega Drive - Mode 1 CD (2026-06-18)".
Reason: "Sega - Mega Drive - Mode 1 CD (2026-06-18) fast resume rejected.
file_stat(D:\ROM\0 - RP Hacks\Sega - Mega Drive - Genesis - Audio Hacks (2026-08-15)\Sega - Mega Drive - Mode 1 CD (2026-06-18)\RoboCop Versus The Terminator (USA) [Mode 1 CD hack by Bonemagee & RazorZenon v20250217].zip): mismatching file size"
The reported file size is actually correct.
Original filename:
"RoboCop Versus The Terminator (USA) [Mode 1 CD hack by Bonemagee & RazorZenon v20250217].zip"
File size: 1.393.013 bytes
Steps to reproduce
1 - Create a torrent containing the file above.
2 - Add the torrent for seeding.
3 - qBittorrent reports "mismatching file size" as above.
Result:
1 - The torrent does not reach 100%.
2 - Missing pieces are reported.
3 - The file name is reported is reported in the log.
Additional context
I verified the following:
The file exists at the expected location.
The file size matches.
The ZIP archive passes integrity tests in WinRAR and 7-Zip.
The ZIP was recreated from scratch.
Recreating the torrent does not help.
Rebooting Windows does not help.
Creating a torrent containing only this file still reproduces the issue.
Removing this file from the folder makes the remaining torrent verify at 100%.
Most importantly:
Renaming the file to "RoboCop Versus The Terminator (USA).zip" fixes the problem.
I also tested:
1 - Removing only the '&' character.
2 - Removing only the square brackets.
3 - Removing both the '&' and the square brackets.
The problem still occurred.
At this point the only confirmed trigger is the original filename (or some combination of its length and characters).
Expected behavior
qBittorrent should accept the torrent and validate the file correctly when the file exists and its contents are unchanged.
Log(s) & preferences file(s)
qBittorrent.log.txt
qBittorrent & operating system versions
qBittorrent: 5.2.3 (downloaded from official website)
OS: Windows 11 x64
Qt: 6.10.3
libtorrent-rasterbar: 1.2.20.0
What is the problem?
I found what appears to be a false "mismatching file size" error during fast resume validation.
The issue is reproducible with a specific filename. The file contents are valid and unchanged, but qBittorrent refuses to resume the torrent and reports:
22/08/2026 01:01 - Failed to restore torrent. Files were probably moved or storage isn't accessible.
Torrent: "Sega - Mega Drive - Mode 1 CD (2026-06-18)".
Reason: "Sega - Mega Drive - Mode 1 CD (2026-06-18) fast resume rejected.
file_stat(D:\ROM\0 - RP Hacks\Sega - Mega Drive - Genesis - Audio Hacks (2026-08-15)\Sega - Mega Drive - Mode 1 CD (2026-06-18)\RoboCop Versus The Terminator (USA) [Mode 1 CD hack by Bonemagee & RazorZenon v20250217].zip): mismatching file size"
The reported file size is actually correct.
Original filename:
"RoboCop Versus The Terminator (USA) [Mode 1 CD hack by Bonemagee & RazorZenon v20250217].zip"
File size: 1.393.013 bytes
Steps to reproduce
1 - Create a torrent containing the file above.
2 - Add the torrent for seeding.
3 - qBittorrent reports "mismatching file size" as above.
Result:
1 - The torrent does not reach 100%.
2 - Missing pieces are reported.
3 - The file name is reported is reported in the log.
Additional context
I verified the following:
The file exists at the expected location.
The file size matches.
The ZIP archive passes integrity tests in WinRAR and 7-Zip.
The ZIP was recreated from scratch.
Recreating the torrent does not help.
Rebooting Windows does not help.
Creating a torrent containing only this file still reproduces the issue.
Removing this file from the folder makes the remaining torrent verify at 100%.
Most importantly:
Renaming the file to "RoboCop Versus The Terminator (USA).zip" fixes the problem.
I also tested:
1 - Removing only the '&' character.
2 - Removing only the square brackets.
3 - Removing both the '&' and the square brackets.
The problem still occurred.
At this point the only confirmed trigger is the original filename (or some combination of its length and characters).
Expected behavior
qBittorrent should accept the torrent and validate the file correctly when the file exists and its contents are unchanged.
Log(s) & preferences file(s)
qBittorrent.log.txt