CAB archive is corrupted ...

[Florio]

I know this topic has been discussed before, but the replies given have varied greatly.
I performed my weekly thorough scan this afternoon, and for the first time I got a message telling me that some files couldn't be scanned because the CAB archive is corrupted. Forgive my ignorance, but aren't CAB files generally associated with CD/DVDs?
I did save various programs onto CD this past week so as to install them on my young son's PC which has no internet connection. But no discs were in the disc drive of my laptop when I performed the scan earlier today. And all my temp files had been removed.
Could this corrupt CAB archive message be due to the fact that Windows performed its automatic update last night? Would appreciate any advice and/or suggestions on what to do.
Florio

[DavidR]

Cab files can be on any form of media, the notice should have told you what the location and file name was ?

Corrupted Archive file, this could simply mean that avast is unable to unpack it to scan the contents of the archive and assuming it is because it is corrupt. Even if it were corrupt there is nothing that a user can do to resolve any corruption, short of replacing the file.

[Florio]

Thanks for the reply, David. I performed a further scan this morning to get the name of the 'corrupt' archive. As I suspected, it must be something that Windows automatically downloaded:
C:\\Windows\SoftwareDistribution\Dowload\...\mpasdlta.vdm
Do you have any idea as to what this particular file could be? Do you think I can delete it without problems?
Michael

[DavidR]

You're welcome.

I personally don't know of the file, but my friend 'google' does, it appears to be an Microsoft AntiSpyware Definition Update, http://www.google.co.uk/search?q=mpasdlta.vdm, this is the first hit in that search, http://www.bleepingcomputer.com/filedb/mpasdlta.vdm-41695.html.

So I would say that a) this archive file is likely to be encrypted being a signature definition file and b) that may have been the problem avast can't get into the encryption to extract so reports corruption. So I would say nothing to worry about.

Remember - Files that can't be scanned are just that, not an indication they are suspicious/infected, just unable to be scanned.