Avast Home 4.8 unable to complete Standard/Thorough scan - freezing.

[Buffalobiian]

To start off, here's my computer specs:
Windows XP SP2 32bit, C2D 2.4Ghz, 3GB memory, HDD1 (Partition C, E), HDD0 (Partition F)
Avast 4.8 Home running IM, Network, P2P and Standard shield on HIGH. Other shields are off.

How it started

I decided to scan my computer yesterday. I can't remember the last time I scanned my computer. In the past, I have ran Local Disks -> Thorough Scan WITH Archives without a problem.
Yesterday, I performed that action, and the scanner would not get past the folder C:/Sierra. There was no CPU usage, and the HDD wasn't being accessed by any Avast modules neither. The progress bar would be moving, thinking it's still scanning, however. Clicking "pause scan" would "pause" it. Clicking "stop scan" would result in a confirmation message, and when I click yes to that, it would become unresponsive. I would then have to shut down the computer via the start menu. During shutdown, there is no "Program is not responding" error, mind you. If I instead click  the top-right cross on the splash screen, it would likewise ask me for confirmation, but it would close the splash screen and current scan without a problem. In all cases, besides the Avast program, the computer is otherwise responsive.

The Simple-scan log does not display any abnormal entries, only displaying the files that are locked or password-archived.

I uninstalled HalfLife, and subsequently deleted the directory C:/Sierra/ and restarted the scan. This time, it would produce the same results, except the displayed scanning directory it would hang at is C:/ .

I then uninstalled Avast, rebooted, redownloaded a fresh copy, reinstalled, and rebooted again. During that reboot, the boot-scanner came into play, and scanned all my folders without a problem.

In the boot-scan log, it states it scanned 108,131 files, 9,754 files, with 0 infected.

Using right-click -> properties, the total number of files/folders on my drives combined is: 97,184 files, 9,580 folders. The missing files may be contributed to hidden/system files such as C:/recycler and system restore points etc.

Upon booting back into windows, I initiated another Thorough scan with Archives, and it would hang again, at a different directory. From memory, I think this was some C:/Program Files/<some application> subfolder.

Next, I ran chkdsk /r upon boot, and tried again. Now it hangs at C:/Program Files/WinRAR

Going to My Computer -> C:/ , highlighting all contents -> right-click -> scan with Avast ------ This completes without a problem.
Using the splash panel, going On Demand Scan -> Scan folders and selecting the hard drives in thorough/archive mode results in the same problem. It also happens if I select C:/ only.

Likewise, the problem is present if I wish to try Standard Scan WithOUT Archives.

Interestingly, performing an On Demand QuickScan with or without archives on the entire computer will complete successfully. The data scanned however, is only 35GB in this mode, compared to the >250GB I have, which are mostly video and program files.

I have the exact settings on a Laptop, and that completes all manner of scans successfully.

Any idea of what's going on?

[das_hs]

I am also facing similar problem. I will say that avast seems to scan 37% in through scan mode with scan compressed file included. After that it hangs at different folder locations. I will check the number of files scanned before it hangs and tell you later. But it is always 37% on my 160 GB HDD with partitions C and F. 

[YoKenny]

I hope you are running Windows Service Pack 3 that has been available for over a year that provides several Critical Security updates and performance improvements so should be applied in IE by going to Tools then Windows Update then downloading and installing all updates.

You should go to Control Panel then Automatic Updates then select Automatic (recommended) or at least Notify me but don't automatically download or install them.

Its not necessary to scan compressed files as they will be scanned when they are de-compressed plus some compressed files could be very large causing avast! appear to hang.

[Buffalobiian]

What I did that fixed the problem was to add the *\system volume information folders of each partition into the exceptions list. I use Zone Alarm, and I remember reading something about a ZA file in there that doesn't respond to Avast, causing it to hang.

[DavidR]

Your fix is a bad idea as it excludes the whole system volume information area and leaves a massive hole in your security. If you have an infected restore point when you use system restore that includes your infected restore point you reinfect your system.

The recommended work around for this is to exclude the tracking.log file.
- Slow Scan or Frozen Scan & Zone Alarm:
There have been some issues with zone alarm in the past and personally I don't feel it is a particularly good firewall, becoming rather bloated and the free version crippled in the strength of its outbound protection (in the hope you will buy the pro version).

One of these problems relates to the tracking.log file located in the c:\system volume information folder/s (more than one if you have more than one partition). By excluding this file from on-demand scans seems to break this issue with ZA and the tracking.log file, see below.

- avast! Program Settings > Exclusions > Add and enter or copy and paste the following bold text ?:\system volume information\tracking.log. The ? is a single character wildcard which is used for the drive letter, this allows for the possibility of more than one :\system volume information folder, so you don't have to have two or more entries in the exclusions list.
Try adding that exclusion and see if that works by doing another scan.

[das_hs]

I am using SP3...