system
10
Just found what appears to be a bug in the latest version of Avast Free… if you uncheck the Settings >> Silent/Gaming Mode >> ‘Silent if a full-screen application is running’ option, the Avast screensaver, when ran, will show the “Failed to initialize” error.
Checking the above-mentioned checkbox (so Avast is ‘silent’ during full-screen application usage), the screen-saver again scans normally.