- 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. This I wouldn't recommend (especially if this is for archives in the \System Volume Information folder, part of the system restore function) unless you are getting problems relating to that file outside of the avast scan.
This one C:\WINDOWS\Temp\_avast_\unp37475553.tmp is wher avast unpacks files that it is going to scanned and under normal circumstances on successful completion of a scan this _avast_ folder should be cleared by avast.
The underlying question is why did it remain in that temp _avast_ folder.
What other security based software do you have installed (anti-spyware, etc.) as interception by another security program so that it can scan it could stop avast from clearing its temp folder ?
If you have other resident anti-spyware applications installed you should add the C:\WINDOWS\Temp\_avast_ to its exclusions/ignore list/s.
