SOLVED Latest version [MultiCommander_x64_(6.9.0.2303)] quarantined as malware

[Blazen16]

A strange behavior of 6.9.0.2303 in Windows 10. When copying a large folder between two USB folders, Kaspersky Internet Security quarantines the multicommander.exe as malware. I removed the program, downloaded a fresh copy, scanned the downloaded exe for viruses (nothin found) and reinstalled it.  I scanned the installed exe for viruses (nothing found). No problems with copying individual sub-folders. However,  Kaspersky intervened again when copying the large folder with many sub-folders.  I again removed the program and installed the previous version [MultiCommander_x64_(6.4.8.2265)].  This earlier version seems to copy the large folder (50 GB) just fine (the operation is still in progress as I write this).

Has anyone experienced a similar problem?  Any idea what causes it?

[Mathias (Author)]

Not sure why that is happening for you but MC have no malware.
Even Virus Total give it a clean pass.
https://virustotal.com/en/file/bccaa68fabe61f0dc65e2068ab132d090cd56a190b7a26d265717c5813593de6/analysis/1482839512/

Sound like there is some issue with the files in that large folder that you access.
If press Ctrl+L in MC you will see the log, and if you watch the file operation log you might see what file it triggers one.
And if you do it multiple times you can see if it always fails on the same file.

[Blazen16]

Thank you. I have confirmed that the executable file of the new version passes the Kaspersy's scan.  I will scan the files being copies and report back.  The puzzling thing is why this behavior occurs only with the latest version.  The previous version copies the same files without any interference form Kaspersky.

[Blazen16]

It must have indeed been a file in the large folders being copied. These folders contained some old engineering programs (not commercial), which may well had something in them that would be confused with the malware in today's world . Is seems that the Kaspersky quarantines not only the suspected file but also the program that saves it to a disk.  I performed a clean installation of 6.9.0.2303 and tested it on large folders that has been confirmed to be virus/malware free by Kasperky scans.  It works just fine.