Im getting file corruption with comodo antivirus enabled.
This only seems to happen on external drives.
I’ve been working out of my laptop for the last year or so and as a result have collected
a number of external USB HDD’s for storage.
Recently while moving files between 1 computer and another I ran into several corrupt files.
At first I thought it was the usb cable… maybe a short, but swapping to a new cable corruption continued.
Windows reports no drive errors in event viewer.
So I started conducting tests with 200 files totaling 75gb, I hashed the files (sha1)
after several days a pattern emerged, with AV enabled I always had at least 1 corrupt file,
With AV turned off no errors in about 2 dozen runs.
I’ve noticed this happening on both computers I tested, 2 different drives, and 3 different cables.
I use to use avast but about 1 1/2 years ago switched to using comodo on all my windows systems.
I’ve started auditing my other external drives for corruption and continue to find files bad… these drives are rarely used.
as they are for archival data.
Both computers tested was windows 7 based (basic 32bit [amd cpu] & home premium 64bit [intel cpu])
I’ve found 1 way that seems to eliminate the problem with AV still enabled, But it’s not ideal.
By default windows will disable write caching for external drives… so if you yank the plug without ejecting properly the chance
of file corruption is minimal… you can optionally enable write caching on external drives and this seems to alleviate or possibly eliminate the problem.
I think this is why I have only noticed corruption on external drives, not internal drive (C:)
It needs more testing but on the 5 runs with write caching on I had no errors on external drive.
Has anyone else ran into this?
The insidious thing about this windows reports no errors in the logs, chkdsk says every thing is great.
and unless it’s something easily tested like a archive (zip, rar, 7zip) you have to have file hashes to compare.
audio, video, text, etc, are harder to test with out a good hash to compare.
To be clear these tests was carried out without unpluging the drive, so it’s not a case of me yanking the cord without ejecting.
I have a theory that with AV enabled comodo is locking up parts of the file while scanning in real time and is causing corruption.
comparing bad files via hex editor usually showed a small continuous chuck of the file is garbled not the entire file.
The external drives are all NTFS formatted.