Why is Avast Service using the CPU constantly

Avast Free Antivirus / Premium Security
1

Iv noticed recently that Avast Service is constantly using 15-30% of my CPU. Its never done this before, it worries me because Avast used to be very resource friendly. Did the last update cause this?

2

Noticed the same after I upgraded to version 17.8.2318 (build 17.8.3705.240) that Avast now constantly utilise around 30-35% of the CPU and it’s not scanning or doing anything productive or at least not what I can see from the GUI…

3

Can you please dump the AvastSvc.exe process using Task Manager and provide dump file?

4

Tried with both regular and admin user and AvastSvc.exe doesn’t allow me to do a dump file. Tried with other processes where there isn’t any problem to perform this task. Any specific settings that needs to be changed for Avast for this to work out?

5

Ah sorry, you need to disable self-defense first.

6

Okay, next question, where would I upload this 502MB compressed file?

7

Use our FTP server please: https://support.avast.com/en-us/article/FTP-file-upload

8

Done!

9

Thank you khavusr, according to dump you provided Software Cleanup engine (SWCUEngine.dll) ate over 3 hours of your CPU time. Will contact developer responsible for SWCU.

10

Ok. Fair to mention that this occured after that I upgraded to the mentioned version this Sunday afternoon. But, hope that this helps and don’t hesitate to comeback if you need to collect additional information or perform som tests.

11

Any update on this topic?

12

Update your VPS and reboot. Better now…?

13

Not fixed yet, I’ll let you know once issue is resolved

14

Wasn’t it fixed with the SWCUEngine update to V12.1.153.0 yesterday…??

15

I am also experiencing large CPU usage by Avast - it says it is the Behaviour Shield which is constantly using around 50% of CPU, even when I am doing nothing else. I am new to these things so tell me what info I need to provide.
Version is 17.8.2318 (Build 17.8.3705.249)
Running Windows 10. Browser is Chrome
Active Subscription to Avast Internet Security
Paddy

16

Must be different case, because behavior shield has its own process aswidsagent.exe. Can you please dump the the process?

17

I am happy to do so - but please explain how and what to do with the dump!

18

I have worked out how to do the dump and checked I have Administrator access, but when I try I get an “Access denied” message. From previous posts I suspect I have to turn off “Self-defense” but how/where do I do that?

19

OK - I finally managed to work out how to turn off self-defence and have created and uploaded the dump as requested under name paddy_bowen.rar and following your instructions on passwords etc.
LMK if you need more - Avast Behaviour Shield is still using around 50% CPU and affecting other applications on my laptop.

20

As it looks like no one will be looking at this again until Monday I have tried a few other things, the results of which may be useful:

  1. I tried turning off Behaviour Shield. Interestingly this made no difference to the CPU usage for the process UNTIL I restarted the laptop.
  2. After restart, CPU usage was down to around 0.5% - very acceptable.
  3. I turned Behaviour shield back on and CPU usage did not change. Concerned that the turn on would not take effect until I restarted, I did that.
  4. After restart CPU was still under 1%. I selectively started other Apps - Chrome, Windows Media Player and File Manager are the three I use most. None of these had any effect on the CPU usage of Behaviour Shield.

So at present I am back down to sensible levels - I will report again if this changes.