I think i found a bug is this latest Avast free 2015 RC1 
Today i tried to use windows update but i was allways getting this error code:803D000A and was unable to download any update.
Disabling the web shield resolved the problem.
Is this a known bug?
PS: I’m using Windows 7 Home Premium 64bit
I don’t seem to have that issue. Update seems to be working fine here.
+1
Run the following tool and you’ll probably solve your problem:
http://answers.microsoft.com/en-us/windows/forum/windows_7-windows_update/windows-could-not-seach-for-updates/05f2f08c-d22d-46af-aa36-bac73fb5bc12
If this fixes your problem, it certainly wasn’t avast! related.
hi bob3160 
Thank’s for the link but after i tried all the tools the problem still persists. Windows update only works when i disable the Avast web shield.
Anything else we can try? :
Yes, check and make sure that webshield is allowed access through your firewall.
Avast has full access to the internet. The only way Windows update works is when i disable the web shield.
It’s strange that i’m the only one reporting this but maybe is some bad configuration in my computer… :-
Time to investigate more 8)
Remove all rules referring to avast! from your firewall reboot and have it again ask you for permission.
I did what you told me but i’m affraid the problem remains.
I forgot to mention earlier that i’m using the windows 7 firewall
Only one other thing I can think of to try:
Turn off the windows firewall once that’s done, go to your last post in this thread:
https://forum.avast.com/index.php?topic=156282.msg1132549#msg1132549
If that works, it’s not avast! and we’ll have to rack someone’s brains to solve the problem.
Did all you told me but it’s no good
Indeed we need more brain power to solve this
Have you tried a clean install using the avastclear tool.
No need to add avast exclusion to the windows firewall unless you have enable the outbound protection which is disabled by default
I will try a clean install and report back
Thank’s CraigB that did solve the problem. I can use Windows update again ;D
Good to hear
Good to hear but it makes no sense. avast! has never been the cause of blocking Windows updates.
Maybe some corrupt file or some old Avast file still laying around
I guess that old stuff isn’t able to block Windows Update.
It’s not only the free version that is causing a problem!! I have internet sec’ and I can’t update at all!!
It isn’t Avast. Maybe if you describe your problems in your own thread, we can help you solve your problem.