Avast Premium Security Full Virus Scan Does Not Complete

Avast Free Antivirus / Premium Security
1

I have been using Avast for about 6 years now. I run it in conjunction with Malwarebytes and have had no issues till yesterday.

I am running Windows 10 Pro
Version 1809
OS Build 17763.678

Hardware configuration:
Intel i5-8600 3.10 GHz processor
16 MB RAM
64 bit

I run a scheduled Full Virus Scan on Sundays and for the first time, it hung, after completing 54%. I tried restarting the scan, rebooting the computer, etc. Nothing worked, but each time the scan stopped at 54%! I have tried to redo the scan 7 times and each time it hung at 54%.

I called Tech Support and after doing some remote diagnostics, they said that I would have to pay to do some ‘Advanced Diagnostics’. I did not want them poking around the machine as I have noticed nothing else awry – everything else works just fine.

I got curious about the fact that each time it stops at 54% and found that the particular file where it stops is

amd64_microsoft-windows-m…ty-backcompat-tlb28_31bf3856ad364e35_10.0.17763.1_none_a28d7c61d6398fe8

in the Windows\WinSxS\Manifests directory.

It is a tiny file (440 bytes)! Is there any reason Avast would choke on this? And, if
it does have problems reading it, why does it not flag that and go one to complete
the scan?

Also, I must add that I did a Smart Scan and it successfully completed and flagged
nothing out of the way.

Any help would be appreciated. Particularly regarding recent Windows 10 updates
as I did seem to get one a few days back (after the last successful Sunday scan).

The most worrisome part is whether the Firewall part is working. It make me doubt
the entire package. Luckily, I do have Malwarebytes running as well. As I stated at
the outset, there have been no conflicts up till yesterday.

Thanks for your help.

2

Ooops! Forgot to add the Avast information.

Avast Internet Security

Program Version: 19.7.2388 (build 19.7.4674.524)
Virus Def Version: 190902-0
UI Version: 1.0.402

Thanks!

3

Tried one other experiment.

I ran a Targeted Scan on the WinSxS folder. Ran successfully to completion!

Then tried a Full Virus Scan. It hung at 54%, though at another file (in the Windows directory). The recurrence of 54%, every time, is beginning to make me suspect that something has recently changed in Avast and that it is bumping into some kind of memory limit … or something like that.

Suggestions and ideas are greatly appreciated.

4

Repair Avast:

  1. Avast GUI → Settings → Troubleshooting
  2. Click on ‘REPAIR APP’.
  3. Follow instructions.
  4. Reboot.
5

my smart scan got stuck at resolving some issues . but when i closed avast and opened it again i noticed the virus was already moved at the virus chest … so am still wodering what the lag was all about

6

J2roc Would you be able to create a dump of AvastSvc.exe process at the moment it’s stuck at those 54% (e.g. from Task Manager - rightclick on the process and select Create dump file) - and then compress and upload the dump somewhere?
(It can be uploaded to ftp://ftp.avast.com/incoming under a unique name, or to a file sharing service of your choice.)
Thanks.

7

Thanks for the suggestion … but it did not work. Ground to a halt at 54% on a
simple JPEG file on my Desktop.

8

I did find the process, but I could not create a dump file. Got a message saying “Access is denied”.

Any suggestions to get around that?

I am the admin for the computer. But, it did not ask me for any authentication. Simply
said “Access is denied”.

Thanks.

9

Disable Avast self defence (Settings → Troubleshooting).

10

I tried it: Disabled Self Defence, Repaired again, rebooted.

Now hangs at 55%!!!

I am leery of running anything like an antivirus software with self protection, anyway,
and so I have turned on Self Defence again.

One thing left is to uninstall Avast (Security and VPN) and try a clean install.

If that does not work, I will live without the scans. Malwarebytes does them as well.

Thanks.

11

My answer was in reply to:

So you can provide the logs requested by Igor in Reply #5.

12

What log files? The ones in ProgramData/AVAST Software/Avast/report ?

I can certainly create a RAR archive and upload, if that is what is being asked.
But these files are a far cry from a dump.

13

Did a complete uninstall and reinstall.

Now, a Full Virus Scan stalls at 69%!

Oh, well. Just will live with it.

14

With Avast self-defense disabled, you’re still getting Access denied when trying to create a dump from Task Manager?

15

igor,

I misunderstood Asyn’s suggestion. I now realise that he wanted me to try create the
dump after the disabling. I did and it worked!

I have compressed it using WinRAR and have transferred a zip file to
ftp://ftp.avast.com/incoming.

The filename is AvastSvcDMP_J2roc.zip.

Hope this helps.

Thanks for all your assistance.

16

Please try to put the path C:\ProgramData\Microsoft\Network\Downloader\qmgr.db to scan exceptions; that seems to be the file that (according to the dump) can’t be opened and is blocking the scan.
We have a hypothesis what might be the (general) cause and we’ll try to modify the scanner to avoid this - but it will take some time.

17

Hurray! That did it!!

Thank you very much for this. You saved me some money that the Tech Support
guys said that I had to pay for them to run “Advanced Diagnostics” using “a very
sophisticated tool” to see what was wrong with my system.

However, I would expect any programme that works its way through a filesystem,
trying to open/read files, to just flag a file that it cannot open/read
and move on. Perhaps a future update of Full Virus Scan will be modified to do that.

I did see that several Windows updates failed, while others successfully installed.
There is some stuff on the web about problems associated with qmgr.db. I wonder
if the failed updates and the potentially broken qmgr.db are, in some way, connected.

Anyway, thanks a lot for resolving the issue.

18

Well if opening the file simply failed, then sure, we’d move on… but in this case the operating system’s “open” function doesn’t return - that’s where it gets stuck.

19

I manually installed Windows Update 1903. Took for ever, but it ran, and it seems to have wiped out all the failed updates as far as what I see in the Reliability Monitor.

Do not know if the failed updates are the sources of the problem, but it may be something for you to consider.

Will follow up this Sunday, when the next Full Virus Scan is scheduled to run.

Thanks again, for your help.

20

Scheduled Full Virus Scan successfully ran to completion.

Thanks again.