Avast and corrupt files

[sjadventures]

When I do a boot scan Avast shows me that I have 3 corrupt files. Does Avast do anything with these corrupt files (fix, delete, etc) or is it just alerting me to the fact that they are there?

[Pondus]

antivirus programs will only do something (clean / quarantine / delete) with infected files

so this is just a scan error message

[Lisandro]

By examining 1) the reason given by avast! for not being able to scan the files, 2) the location of the files, you can get an idea of what program they relate to. You may need to expand the column headings to see all the text.
Files that can't be scanned are just that, not an indication they are suspicious/infected, just unable to be scanned.
Also, the packaging of the file could have some error, or use a non-standard pattern...

Clean, Quarantine, or Delete?
http://antivirus.about.com/b/2007/03/11/clean-quarantine-or-delete.htm

[sjadventures]

So your saying that a corrupt file just means Avast cannot scan it? How do you fix or delete a corrupt file or do they need to be fixed or deleted?

[magna86]

@sjadventures

Can you please provide us the exact location and filename of the detected files?

[cadremis]

A few weeks ago I made a boot Scan in Firend's Vista PC and Avast said that it could not scan several files because they were corrupted, and I fixed it doing a disk check on the computer and it took away corruped files and replaced them with good ones.

rm

[sjadventures]

A few weeks ago I made a boot Scan in Firend's Vista PC and Avast said that it could not scan several files because they were corrupted, and I fixed it doing a disk check on the computer and it took away corruped files and replaced them with good ones.

rm

Can you advise on how to perform that?

[Pondus]

How do you fix or delete a corrupt file or do they need to be fixed or deleted?

It depends what the file(s)are fore....
so if you answer magna86 question we may be able to tell you....

[DonZ63]

Since when do AV scanners check for corrupted files?

What are the corrupted files?

Sounds to me like Avast is finding corrupted Avast files. In that case the solution is to repair or reinstall Avast.

[sjadventures]

Below is exactly what one of them said.

C:Documents and Settings \ Circuit City\My DocumentsDownloads\vcredist_x86.exepart|>vc_red.cab|>mfc90u.dll.30729.01microsoft_vc90_MFC_x86.SP Error 42127 {CAB Archive is corrupted}

[DavidR]

Since when do AV scanners check for corrupted files?
What are the corrupted files?
Sounds to me like Avast is finding corrupted Avast files. In that case the solution is to repair or reinstall Avast.

They don't specifically scan for corrupt files, but the try to unpack archive files. If they are unable to unpack them they could well be corrupt and that is what is being reported, a file cant be scanned and the reason corrupt archive, etc.

You can't speculate as to what these files are when the OP hasn't reported what these files are, file name and location. So we have to wait his answer to that question.

Now that he has just answered that they aren't avast files.

[DavidR]

Below is exactly what one of them said.

C:Documents and Settings \ Circuit City\My DocumentsDownloads\vcredist_x86.exepart|>vc_red.cab|>mfc90u.dll.30729.01microsoft_vc90_MFC_x86.SP Error 42127 {CAB Archive is corrupted}

Well the important part (excuse the pun) is vcredist_x86.exepart, and that appears to be a failed download as part is normally tacked on to the partial download before it has completed the download.

Since the file is incomplete and avast tries to extract the contents, part of the file is missing (corrupt) and that is why (the reason) the error is reported on a file that couldn't be scanned.

[sjadventures]

Are the 3 corrupt files something I need to correct or delete and if so how? The other 2 were very similiar to the one I posted but did have a little variation but the front part of each corrupt file was the same. All of them included the part

[ady4um]

As DavidR said, these are not filesystem corrupted files (so, nothing to do with chkdsk).

These are part of a CABinet file. Just as zipped files, CABinet files are archive files that can contain folders and other files. And just as zipped files, you could have several files that are acting like a chain:

part001.zip
part002.zip
part003.zip
...

or, similarly,
part001.cab
part002.cab
part003.cab
...

or
part.cab
part.001
part.002
...

The point is, that they are a chain. Each part is not complete. Only opening the complete set, you would obtain the real complete content (imagine 3 CDs of 680MB each part, and you copy all 3 archive parts to your computer to rebuild the original complete archive contents).

In your case, either one of the parts is corrupted (and it simply would need to mistakenly change, say, a "zero" for a "one", and all the complete set could be unreadable); or Avast is not able to understand this particular set of archives.

In any case, this does NOT necessarily mean that the archive (or a part of it) is infected. It may, or may not be. All that Avast is reporting is that, as far as Avast understands, the set of files that conform the complete set of archives can't be opened and then scanned by Avast.

One explanation could be that one part of the set is not located in the expected folder, hence Avast doesn't know how to open it. Whichever the reason, is not telling you "anything" definitive about that archive.

[sjadventures]

I understand the explanation and I am very appreciative of all the help but still do not know if I need to deal with the 3 corrupt files or ignore them.