Reenable autosandbox in avast! Free

Hi, I just globally switched off autosandbox from a dialog that popped up because of a file rated as suspicious. Now I want to reenable the feature but cannot find it anywhere in the user interface. Where is it?

Thank you!

Ooops, posted too early. I found a reference in the online help pointing to the file system shield’s settings. Sorry for the noise.