Well, it’s rather strange that it would “scan a few files and display message ”… if the scanner fails to initialize, it shouldn’t scan any files, I’d say.

Some more info is needed… what version (build) of avast! is it? Did anything change when this feature stop working? (like, a new screensaver was set, a new software was installed to the computer, …)

The other scanners (e.g. the Simple User Interface) work without problems when the disk is scanned?