Does Avast scan of its own ? High AvastSvc CPU usage...

Using here Windows XP+SP3 and Avast Internet Security, not the free one, licensed until June 2015, version 2015.10.0.2206

I notice from the Windows Task Manager that very often AvastSvc.exe takes one of the two cores of my CPU for its own use…
If I disable the shields control, then it stops eating CPU, and also when I re-enable the shields control it stays down. But if I tell Thunderbird to read my email, it goes up again at 50% CPU (one core…), and stays there even when I close Thunderbird.

Only disabling (and then re-enabling) the shields control puts it at rest…

Does perhaps Avast do, let’s say, a root kit scan of its own, without being commanded to ?
Otherwise I can’t understand the reasons of that high CPU load…
I even tried the suggestion to put in WebShield.ini the two rows :

[General]
UseStreamFilter=0

but to no avail…

Suggestions ? Thanks

Install the latest avast version and check if the problem is still there.
Latest version is 2015.9.0.2208

I tried to update, using the Update function in Avast.
But it told me that I am already up to date (current version 2015.10.0.2206) …

How can I get 2208 ?

You have the latest regular release version of avast, currently there is a beta phase ongoing for an SP1 for avast 2015. See https://forum.avast.com/index.php?topic=159263.0 which is for 10.0.2207 once installed you should be able to update that beta for the latest refresh 10.0.2208.

Note this is a beta with all that it entails.

Thanks, but I am not too keen to install a beta version of an antivirus on a machine where serious software development work is done…

As far as I remember, with Avast 2014 I had never noticed this hungriness of AvastSvc.exe … it started with 2015.
I can stop it with by disabling the real time shields control, but this would defeat the very ultimate goal of an antivirus…

Still waiting for a solution, thanks.

UPDATE :

I enabled the Windows Firewall (just to not remain without a firewall…) and disabled the Avast Firewall.
The problem disappeared… now AvastSvc is almost at the end of the list of processes ordered by CPU load…

So the Avast Firewall seems to be the culprit… hope this can be of help to the Avast developers (supposing
they are monitoring this forum…)