"Behavior Shield" is blocking most applications

Running AVAST free on Win 10 x64.
Launching most applications gives an error message reading “The application was unable to start correctly 0xc0000005.”
Tried disabling all the shields and the same applications worked fine.
With a little bit of experimentation, I figured out it is the behavior shield causing issues.
Please help know whether it is a bug in the program itself or on my system, and if it is the latter, how I can fix it.
I have already tried uninstalling and reinstalling AVAST using the avastclear utility, but that achieved nothing.

  • Which version of Avast Free…?
  • Other security related software installed…?
  • Which AV(s) did you use before Avast…?

Apologies for the late response. I’m running 19.5.2378 (build 19.5.4444.505) with Virus Definitions version 190620-2.
I got Malwarebytes running concurrently and the only security software I’ve used on this system is this combination: Avast (free) + Malwarebytes.
However, with trial and error, I’ve found out that MB is not causing the issue.

Curious, When you say ‘trial and error’ did that include completely uninstalling Mbam and using the “Malwarebytes Cleanup Utility” to see if there’s any change in your issue?

Edit

I admit it didn’t include anything with MB because I started with Avast and turning off the behavior shield did fix the issue. “Trial and error” here really meant trying disabling random shields and seeing if it fixed the issue.
I will try the same with MB and get back.

Update to the latest version (19.6.2383): https://forum.avast.com/index.php?topic=228012.0

Updated Avast; cleaned MB. Still the same.
Turning off the “Behavior Shield” still does fix the issue.

Sounds like a Windows error and problem not Avast. See if this helps:https://blog.pcrisk.com/windows/12778-how-to-fix-application-error-0xc0000005

sfc /scannow - no errors
Malware scan - clean
Registries fixed (CCleaner)
Drivers updated.

The problem is still there.
Only turning off Avast Behavior Shield seems to resolve it (even if it’s just a workaround).

Regarding Avast & Malwarebytes, see: https://forums.malwarebytes.com/topic/200324-exclusions-for-avast-users/

Will try that after I reinstall Malwarebytes.
Currently, I had cleaned MB as instructed above (without reinstalling) and it didn’t resolve the issue, so I don’t think it’s spectacularly likely.

Could you provide any examples - which apps get blocked…?

Due to another bug (not related to Avast), I had to reset my PC, and apparently, the error was indeed related to a corruption in the OS files masquerading as an error with Avast.
The system is now back up and running with Avast & MB as usual.
Thank you to everyone for their time.

You’re welcome. And thanks for the feedback.