Oracle VirtualBox conflict

Hello all,
I was happy with Oracle VirtualBox and avast!.. until 31st of March. Since then, VirtualBox could not start any of VMs. The error is 0xc0000005. VirtualBox logs show there is nothing but Windows kernel and avast! So I really suspect some conflict. I upgraded both VirtualBox and avast to the latest versions. I also tried the disable avast virtualization. Nothing helps. I really need my VM!
Host: Windows 8.1 x64, avast Free.
Guests: DOS, Linux, several versions of Windows.
Is there any good solution? (uninstalling avast isn’t)

Are you running the latest version of Virtual Box released April 2?

I did update. The actual version of VirtualBox is 4.3.26 r98988

Try a repair…(In the Virtual Box)…Control Panel>Uninstall a Program>double click “avast”>click “repair”>reboot.

If that fails try a clean install of avast using http://files.avast.com/iavs9x/avastclear.exe when prompted to reboot into safe mode click “yes”.

I’ve found that! It is not avast that causes compatibility problems, it is another application.

Glad to hear you found the answer to your problem.
If you ever need any more assistance please feel free to come back.

If you are comfortable helping others please, by all means, become more active here on the forums.

It would be interesting and might help others to know what that incompatible “other” program was. ???
Thanks