Cannot scan files

[earth_grinder]

Everytime I do a full scan of my computer with Avast 4.8 there is always a list of files that are listed as files that could not be scanned.  Is there any particular reason these files can't be scanned for a virus?

[Pondus]

This must be the question most often asked in here i think (try forum search)

quote DavidR

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

Many programs (usually security based ones) password protect their files for legitimate reasons such as AdAware and Spybot Search & Destroy, there are others (and avast doesn't know the password or have any way of using it even if it did know it).

[DavidR]

Everytime I do a full scan of my computer with Avast 4.8 there is always a list of files that are listed as files that could not be scanned.  Is there any particular reason these files can't be scanned for a virus?

What avast version are you using 4.8 or 5.0 ?

avast also lists the reason why they can't be scanned, what reasons were given ?
You may need to expand columns to see all the information.

If you can give some common examples of those file names, the locations and reason given why it can't be scanned might help us further ?

[earth_grinder]

Using 4.8 free version.

I went back to look at my last scan log to see some of the files that Avast did not scan and under date of last scan it has "not done yet".  I have scanned my computer several times since using Avast, but there is no record.  What is wrong there?  Do I not have something setup correctly?

[DavidR]

The Home, free version in 4.8 doesn't retain the scan data, once the Simple User Interface is closed the data is gone. So you would have to run the same scan again to return those files that couldn't be scanned with the reason why they couldn't be scanned and location, etc.

There is nothing wrong as there are many legitimate reasons why a file can't be scanned, it is just that some common examples would help us put your mind at rest.

I doubt you have something setup wrong.

[earth_grinder]

I looked at the files that Avast said it could not scan.  All of the files have a file extension of  DAT.  Some are in C:\System Volume Info and most of the others are in C:\Documents and Settings.

[DavidR]

Sorry but that really isn't enough to work with and the most important part is missing, the reason why they can't be scanned.

If you can give some common examples of those file names, the locations and reason given why it can't be scanned might help us further ?

Unfortunately to get that information after so long you would have to run the scan again and collect the information. But as we said generally there is no problem in the fact that files can't be scanned.

[earth_grinder]

The window that gives the files that cannot be scanned is small and I don't know how to expand the window or the individual file name to give the data you ask for.

[DavidR]

How to - Expand Column Width, hover the mouse pointer over the column header divider until the pointer changes (see image, click to enlarge) left click and hold down the key whilst dragging the pointer to the right.

[earth_grinder]

I now am able to read the whole file and why it could not scan the file.  How can I copy that to the forum.  I did a print screen, but the file is too large to upload to the forum.

[DavidR]

Just give some common examples not the whole list, file name, location and reason.

[earth_grinder]

C:\SystemVolumeInformation\_restore{1F4D47CE-2E7F-4AC6-B28D-35721EDC1EF0}\RP163\AD048B73.exe\VUESCAN.DAT\C72B9979.DAT       Unable to scan Archive is password protected

C:\Documents and  Settings\Charlie H Zuck\Application Data\SUPERAntiSpyware\quarantine\..\backup.db
Unable to scan Archive is password protected.

VueScan is scanner software I downloaded a trial version and is not fully functional until I buy it.  All the other 300+ files give the same reason for not scanning.  Most of those files are either VueScan files or SuperAntiSpyware files.  All give the same reason for not scanning - Archive is password protected.

Thanks so much for all your help and being patient with me in getting the info to you.

[DavidR]

As has been said files that are password protected (by the application responsible for the file) can't possibly be scanned by avast, a) it doesn't know it and b) even if it did know it there is no means of inputting it.

SAS is doing what it should protecting the quarantines files.

VueScan regardless of not being functional is protecting its trialware status would be my guess so could be legit.

So I see nothing untoward about what can't be scanned.

Now comes the easy bit, how to reduce this number to zero, don't scan archive files as they don't present an immediate risk, even if something in them was infected. You could also consider the Sensitivity of the scan you are doing, see below.

- Thorough is also by its design very thorough (it scans all files) and perhaps a little overkill for routine use, were a Standard scan without archives should be adequate. Archive (zip, rar, etc.) files are by their nature are inert, you need to extract the files and then you have to run them to be a threat. Long before that happens avast's Standard Shield should have scanned them and before an executable is run that is scanned.

- I have only ever done a Through Scan with Archives once shortly after installation just to ensure a clean start state, but with XP for example avast will do a boot-time scan after installation if you select it, this I believe will be quicker and reasonably effective. Like everything in life things are a compromise.

[earth_grinder]

Thanks again for all your help.  I will make your suggested changes on my next scan.