ashserv CPU burst

[robust]

avast 4.8 Home
winxp pro sp2

Symptoms:
usually happens at 12am - 1am
ashserv.exe occupies 99% of CPU resource,
which is severe enough to cause the screen fails to update (even only using PC for typing or web page scrolling)

Depending on what program I'm using, the symptoms can last from a few seconds to many minutes ( I hard rebooted)

Possible active component: standard shield,
Other components have no change in scan count

I've read a bit from here
http://forum.avast.com/index.php?topic=35172.0

And I've updated to 4.8 for a few weeks because of similar symptoms in older version
But it seems to happen again.

The problem is quite annoying...
Is there a way to alter its priority?
Task Manager won't work. I am using process tamer but still expericencing the symptoms from time to time.

[olddog]

What software do you have on your PC that is set to auto update?

[Lisandro]

Are you using the trial version? Or Pro?

[robust]

Hi, I'm using the trial version.
I do have Windows autoupdate but I think it was not active during that time.
It'd notify me normally to download anything.

ashserv remains high even I stopped the online protection all together and added some exclusion folders which I thought it may be scanning (but safe).

[Lisandro]

Is there any scanning scheduled to run at that time?
You can check into Sessions if anything is running at that time...