Thank you for the info about the Stream Filter, DavidR!
About your questions:
I’ve disabled all the protection for a test, and my CPU still goes to maximum almost instantly when flash player is involved in some way. So, I believe avast! is not the problem here. Thank you anyway!
Don’t know if this applies to your situation but, you may want to try the following:
https://youtu.be/IToxyxi7tRQ
Let us know if that helps. 
You’re welcome.
With XP - some of the new features wont work because XP doesn’t have the interface to handle them, so avast uses the existing (old) methods. Interestingly enough it is these new methods that have cause some slowdown issues, which shouldn’t be the issue here.
Hopefully Bobs youtube clip will resolve your problem.
Hi, I’ve got this same problem now and it’s really Peeing me off.
I’m running windows 8. I’ve tried looking for that “webshield.ini” file bu can’t seem to find it.
I’m not very computer savvy, so any step by step instructions on how to fix this problem will be greatly appreciated.
Thanks for your help.
Michael, you should find the answer you’re looking for in this thread on page 2.
Just by the way, I applied Bob’s fix too, which is what brought me to this thread. It worked!
Thanks.
My pleasure. Glad I was able to help.
Thanks for this great utility, it helped me clear a little over four gigabytes of temp files that were cluttering up my system, but this, nor did a fresh re-install of Avast bring me joy.
Asyn, thank you so much for posting this edit. I’ve an older desktop that’s running Windows XP with Service Pack 3 installed, and I was experiencing a high (100%) CPU usage for nearly a week, and could not pinpoint what was causing Avast to hog up my machine’s entire CPU and resources, despite completely removing, and re-installing Avast.
Since my resources and CPU were being tied down, while AvastSvc.exe was running in the background, I wasn’t able to edit WebShield.ini in Windows normally, and applied the changes, while running Windows in Safe Mode. So far, my machine seems to be running without any issues. I will monitor it, and report with any updates.
After monitoring my desktop for a few hours, the modifications to WebShield.ini did not remedy my problem.
AvastSvc.exe has crippled my system, and even affected Skype, causing it to have critical errors, and disallowing it to run properly.
I’ve uninstalled Avast through Revo Uninstaller Pro, then removed the remainder through Avastclear to ensure that it was completely removed.
I’ve even experienced this issue with the 2016 Beta. Upon installing it, my machine froze. After rebooting my machine, I was back to a crawl, thanks to AvastSvc.exe bogging down my system’s entire resources.
Unfortunately, I’ve uninstalled Avast (yet again) and switched over to AVG until this matter gets resolved.
For those curious, I was running Avast 2015 on a custom-built desktop computer, running Windows XP, with Service Pack 3 installed.
My machine has a Maxtor hard drive, two gigabytes of RAM, an AMD Athlon (XP 2600) Processor at 2.08 GHz, and an American Megatrends Motherboard.
I realize that Microsoft is no longer supporting Windows XP, but my desktop is mainly used for audio production, and I’ve used Avast for ten years.
As I’ve said in my previous post, this problem began, late last Friday (October 16, 2015) so I’m assuming I’ve run into a bad update, or some kind of conflict in my machine.
Any help would be greatly appreciated.
Regards,
Dr. Kosher
My noun in Avast version 10.4.2233 instaled on W-XP/SP3 (two different PC) and slow CPU (about 1GHz).
If user have system setting without password and starting automaticaly to desktop (without login screen) AvastSvc and Csrss is locking together, but if usualy change setting windows to use Login screen and wait about 1 minute before loging - everithing is OK.
Just did it but no success. After a few minutes, the high cpu usage by AvastSvc.exe returns. Any other ideas?
Avast free 11.1.2241
Windows 7 64 bit fully updated
Please note: Avast has changed in many ways/aspects since I posted (check the date!!) this.
If you’ve similar problems with the newer versions I strongly suggest to start a new topic.
I am also having this problem after last update. Windows XP with Lenovo T61 (Core Duo T7500)
Start a new topic: https://forum.avast.com/index.php?action=post;board=2