RPC to slow to scan

I’m getting a message stating RPC to slow to scan. How can I rectify this problem?

What are you doing whe you get that message?

Controlpanel > ad/remove programs > avast > uninstall/change > repair option … wait a minute and reboot

Any change?

What OS/SP ?
What exact version of avast ?
Any other security (related) software installed ? (or did you)
What exactly is giving you the message ?