Got the same problem here on :
- Win7x64 SP1
- system functional since 7 years with no software changes, no windows updates : don't tell me - i know and don't care about win updates. The fact is here that the system was UNCHANGED except for Firefox portable that is updated (EDIT : last update 2 years ago - but uBlock filters updated)
- high security standards (tight firewalls + safe behavior) and no/low source of possible contagion : scans with MalwareBytes, Avast, Clam give no alerts with updated databases (2021.08.26)
- some weeks ago Avastsvc started to go up to 50% and never goes down ; unknown trigger ; i identified the problem 5 days ago but the PC was sluggish since 2-3 weeks
- a full scan hangs at time = 0 on svchost and CPU usage goes up to 99
- "create dump file" on avastsvc process makes CPU back to normal but again 50% after x minutes ; trigger unidentified
- avstclear and cleanuninstalls are no use
- versions 9 to 11 have the same behavior
- turning shields off has no effect either before or after CPU peaks to 50%
- i did a factory reset (2013 system image) with no internet access and installed avast 9 with offline VPS update -> 50% CPU usage
- i did a factory reset (2013 system image) and installed avast 21 with online VPS update -> no high CPU usage but my weak system has difficulties to hold the pace with avast 21
- i did another factory reset with no internet access and installed avast 11 with no VPS update -> no high CPU usage
- i'm updating VPS now on version 11... waiting for a CPU peak (EDIT : confirmed after reboot and 10 minutes)
+ Blues Brother, whom i suppose is not using my computer, has the exact same problem
As of now, i'm guessing : a VPS update is the trigger on high CPU usage for 9-11 versions
I can't reasonably make an avast update : we're talking a weak 2013 netbook here. Or maybe i should install avast 21 with all shields at minimum?
Anyone has an idea?