AvastSvc.exe frequently spiking to 100% CPU usage, even when idle

Avast Free Antivirus / Premium Security
1

For an unknown reason, the AvastSvc.exe process will frequently wind up my CPU, spiking at 100% usage for several seconds, and then dropping back down to its usual ~1-5% idling. This happens regardless of computer usage (even when idle), but seems to occur far more frequently as programs are running (particularly watching YouTube videos in Chrome), which is problematic as it bottlenecks my system into a complete stall until the spike recesses.
This problem has been ongoing for roughly a week. I have searched the forums and other sites for the same issue and found some suggestions, of which I will list.

I’ve tried:

  • Repairing the installation
  • Disabling all shields (I only have file & behavior shield and game mode)
  • Using the avastclear.exe uninstaller via safe mode and performing a clean install

This is a fresh installation of avast! from when I did a clean install of Windows 10 a couple weeks ago (no residual previous versions that are known to cause conflict).
I attempted to find WebShield.ini to add “UseStreamFilter=0” as per a suggestion, but that file does not exist on my system as I am not using the Web Shield component.
I have also tried creating a dump file from the Windows task manager while it’s occurring, but I get an error “The opration could not be completed: Access is denied”. I am the sole user of this PC, as I built it, so, naturally, I am using an administrator account, but this happens regardless.
Otherwise, none of the suggestions attempted have solved the issue. This problem continues to occur, interfering with watching videos, playing games, and even regular productivity.

Can anyone provide insight as to what may be causing this to occur? I figured it might be the file shield regularly scanning files that are being read/written, but the spike occurs even while my PC is idle and I have observed the spike even with the shields disabled. Even while typing this up, it has happened twice. I will provide my specs/OS below, which should convey that this system is intended to be powerful, and this avast! service is severely crippling it at random intervals.
I’ve scanned my system with both avast! and Malwarebytes, both yielding 0 results for infection, so it’s not malware.

I have always used avast! and only avast! since I’ve had my own personal computer, and this has never been a problem until recently. At this point, if it continues, I will have to consider uninstalling avast! in favor of Microsoft’s built in Defender.

Relevant system specs:
avast! Free Edition 18.3.2333 (build 18.3.3860.316)
Windows 10 Pro x64 1709.16299.371
Intel i5-6600K
16GB DDR4 RAM

Edit: For reference, I took a screenshot of the task manager when this spike is occurring. For reference, this is how the process looks normally.

2

Separating this post from the original as slight update.

Checking Windows services, the Avast Antivirus service status is currently stuck at “Stopping”; the process is currently showing minimal processor usage, as expected. I’ve been watching it for several minutes and it never fully stops. The Stop and Start buttons are greyed out while this is occurring.
I’m keeping an eye on the service, and I will see what changes when the process spikes CPU usage. I suspect the service is repeatedly stopping and restarting, though I don’t know why.

Edit: CPU usage spiked again, but the service status never changed. It’s suspended in a “Stopping” state and never changing. I tried forcing the service to stop using taskkill in CMD, but I received a “Provider failure” message; I’m assuming the service is protected by avast’s self-defense feature.
Even after a repair install and a full uninstall/reinstall, the service still had this issue. For now, avast is uninstalled until I have time to figure something out.

3

[s]Next day followup: I left it uninstalled since yesterday and reinstalled it a short while ago. I’ve been observing resource usage since, and so far, AvastSvc.exe has not spiked during the same scenarios as before. The service itself is running like expected.

I suppose this can be considered case closed. [/s]

Spoke too soon. Just got another few CPU spikes. Service is still running, not stuck in a “stopping” state.

Would be nice to get any sort of acknowledgement or other possible advice. If this continues, I will be forced to abandon avast.

4

Well i had similar issues and i am currently removing shield by shield and component by component.
Dont want to give up on avast,but more and more going in that direction.

5

Glad to see I’m not alone for this particular instance. I’m aware that there have been reports in the past, and all given suggestions have not solved the issue for me.

The last attempt I can think of is to do a custom install and uncheck ALL shields, though I suspect that will not make a difference. Something with the core program’s service is choking my computer for no reason. And I’m a little disappointed none of even the usual forum helpers have replied.

6

Hi,

I’ve just seen your post today - could you first run a repair and restore Avast to its default settings to ensure any changes made haven’t caused this.

Can you then uninstall the game mode component and see if the issue persists? If it does, feel free to install the Game Mode component again.

Finally, can you create a dump of the Avast Service (AvastSvc.exe) process via Task Explorer when the process is spiked and upload it. I’ll get this escalated to the Avast devs once you have uploaded the dumps. Bearing in mind it is the weekend, you should get a reply by Avast for Monday.

PS: You may need to disable the Avast Self Defence via Avast UI > Settings > Troubleshooting in order to create the dump.

Edit: Fixed a typo.

7

Alikhan, thanks for your reply.
Does using the avastclear.exe uninstaller do a clean wipe, including any setting changes? If it does, then I have done this a few times now, restoring avast back to default with each time I do this. This is in addition to a repair install first and foremost, which also did not help (as per my first post).

Otherwise, I again installed avast with default settings, nothing changed, to do as you requested. However, twice now my entire PC has frozen, forcing a hard restart, as the “end process” window appears and reports Windows is not responding. I’m unable to perform ctrl+alt+del. Uninstalling avast again, this does not happen anymore.

I don’t know what’s going on, and it saddens me. I’ve been a fan of avast for years and I have never had any problems with it, let alone shortly after a fresh install of Windows. This only began occurring within the past week or so; no changes to settings or new programs were installed. Seems giving up avast is the only path I must take.

8

Yes, a clean install would reset Avast to default configuration. Without any dumps, it will be difficult to determine the cause. Do you know any others who have the same issue as you?

9

I don’t, unfortunately. Quite a few people I know that use avast have not run into this problem.
When I’m not in the middle of something, I will try once more and see if I can manage to get a dump. I just hope my explorer process doesn’t freeze like it has been…

10

Does unchecking “Enable anti-rootkit monitor” via Avast UI - Settings- Troubleshooting make any difference.

You need to reboot after making the change.

11

Hi thefowles1,
if you are not able to create a dump file there is another option which should not cause any harm/freez -xperf logs

  1. download and install xperf from : https://docs.microsoft.com/en-us/windows-hardware/get-started/adk-install
  2. to start xperf monitor run cmd as admin and type : xperf -on PROC_THREAD+LOADER+REGISTRY+DISPATCHER+Base -stackwalk Profile+CSwitch+ReadyThread
  3. wait for while to capture CPU peak
  4. stop xperf monitor - type in cmd windows : xperf -d trace.etl
  5. zip trace.etl into thefowles1_avastSvc.exe_cpu_peak.zip and upload it into avast ftp
    Thank you for help!
12

Me too!!

I’m seeing avastui.exe pegging my cpu at 100% for the last 1.5 hours. Task Manager cannot kill the process; the message I get is “Unable to terminate process” and “Access denied”.

This is Avast Free up-to-date running on Windows XP Pro SP3 up-to-date, at boot time. This started maybe a week ago, and so far I have been able to restart XP without Avast starting up again.

I do not intentionally run a boot-time scan, and I have picked my options to prevent Avast from doing anything automatically. What’s going on?

13

UPDATE on earlier post:

I turned off the Avast Self-defense, logged out, and logged back in again. Avastui.exe was not running until 10 seconds or so after I logged in, but there it is again at 100% of my cpu.

OK, I’m going to shut down XP, reboot (not restart), and see what happens…

No change after shutdown/reboot; avastui.exe still keeping cpu at 100% with no break… automatic pc fan speed control gradually increasing speeds but cpu temp keeps going up…

Please see 2 Attachments to this post.

14

UPDATE to my 2 earlier posts:

After my shutdown/boot and about 20 minutes of 100% cpu usage attributed to avastui.exe, I was able finally to kill the process with Task Manager. I am now seeing avastsvc.exe at 0%, System Idle in the high 90% range, and no sign of avastui.exe.

15

Hi lanshark4972
can you provide a dump or an xpef log ?
Thank you

16

I’d be glad to do a dump for you if I knew what “Task Explorer” is… please explain…

17

UPDATE: xperf does not run on Windows XP, so that’s not an option for me.

18

Using Process Explorer (procexp.exe) from SysInternals, I created AvastUI Minidump.dmp and AvastUI Full Dump.dmp, zipped them into the folder Dumps of avastui.zip, and sent it per PK’s instructions to the Avast Team FTP server. The upload to the incoming directory was apparently successful.

Since my issue is with avastui rather than with avastsvc, I posted this message to Topic: AvastUI.exe * 32 always uses 25% of cpu’s resources. There is a third topic, Topic: AvastUI.exe using 99% CPU, to which I have not posted because I didn’t see it first… :wink:

Thanks for your attention!

19

Hello
Windows XP SP3
I also had AvastUI using 99~100% of CPU, sometimes never, sometimes forever, sometimes for a period. Prevents some programs (including Winword 97) working. Creates as many problems as the virus’s we are trying to protect against.
Avast recommendation is for version 18.8.2356. NO WAYS! - someone at Avast has missed something.
Changing back to version 17.9.2322 has completely cured Avast’s messing. You have of course then to set Program update to manual to prevent auto updating.
This version is still available on the internet but apparently not from Avast themselves. You need an OFFline version otherwise you get 18.8 again.
Hoping this prevents users battling like I did. Cheers

20

This thread seems to have morphed from CPU spikes due to avastsvc.exe to CPU spikes on WinXP due to avastui.exe.

CPU hogging on WinXP has been reported many times before with 18.8.2356.
Including myself here due to avastui.exe:
https://forum.avast.com/index.php?topic=220639.msg1549868#msg1549868
Also due to avastsvc.exe on WinXP.
https://forum.avast.com/index.php?topic=220639.msg1484900#msg1484900

I followed advice from DavidR, removed 18.8 (the last avast version for XP) and instead clean installed earlier version 18.5.2342.
Note: also need to turn off automatic-updates, otherwise you wll be updated again to 18.8.

Avast 18.5.2342 does not seem to cause the same avastui.exe CPU spikes on WinXP as 18.8 started doing from 6/2020 in my case.

Edit: to include ref to CPU hogging on WinXP due to avastsvc.exe as well as avastui.exe.