Avast Service is using as much proc resources as it can get

[hd.naujoks]

and is extremely slowing down system. Behavior looks like a crypto mining trojan, using up to 90% if nothing else is running on system and getting sometimes reduced to 10-15% with an average of >50% with 0,7 to 0,9 GB RAM usage.

Support request # 15172530 has been filed yesterday but I will not wait for 2 days for any reaction by Avast, I'm short from a full uninstall of Avast to bring my system back under my control.

Config:
Win 10 20H2 Build: 19042.1526 MS Surface Go 128 GB SSD 8 GB RAM
Avast Premium Security: 22.1.2504 (Build 22.1.6921.709)

[Asyn]

Repair Avast:
1. Avast GUI -> Settings -> Troubleshooting
2. Click on 'REPAIR APP'.
3. Follow instructions.
4. Reboot.

[hd.naujoks]

I tried to repair AVAST and after reboot it seemed that Avast Service was consuming less P-time. But trying to work with the system again shows really bad performance. For instance opening the Avast UI takes about 80 s.
What can I do next?

"Open Recorder" minimizes the Avast window but seems to do nothing else. I activated the debug protocol too.

[Asyn]

- Other security related software installed..?
- Which AV(s) did you use before Avast..?

[hd.naujoks]

Ok, switching Avast to passive mode did the trick! System is running fine again. But that wasn't an easy one, it kept removing the check mark twice before I could make it work, probably due to the Avsat Service still running wild in the background. I then ran an Avast full scan over night to make sure there wasn't malware making Avast Service running wild, but results were perfectly fine, no problems found.

Any hint what I could do next to leave passive mode without running into the same problem again?

[bob3160]

Ok, switching Avast to passive mode did the trick! System is running fine again. But that wasn't an easy one, it kept removing the check mark twice before I could make it work, probably due to the Avsat Service still running wild in the background. I then ran an Avast full scan over night to make sure there wasn't malware making Avast Service running wild, but results were perfectly fine, no problems found.

Any hint what I could do next to leave passive mode without running into the same problem again?

Passive mode in essence turn off Avast.
Try the following:

Repair & Clean Install of Avast -> https://goo.gl/t7aJGq
Repair Avast:
Open the Avast User Interface > Menu > Settings > Troubleshooting > Repair App. > Restart the Computer or,
Control Panel> Program and Features (Add/remove program)>Select Avast> Select Repair. Reboot when completed
https://www.avast.com/faq.php?article=AVKB204

If Repair doesn't fix the problem, try the following:
If your Avast settings are not the default settings and you want them restored after the Clean Install, follow this before removing Avast.
https://goo.gl/TXjM7h
Clean Install of Avast:
https://goo.gl/4Ptzkf
If you need additional help with the Clean Install, watch this:
https://youtu.be/p-h3myRD51A