Turned on FileVault, then activated Guest User account. When I go to the Guest account to test it out, Safari is flickering or some would say the screen is tearing. Everything is very slow. Anybody experiencing this graphical bug. Read on another thread that through Guest account could read install logs etc.? Hopefully, 10.9.2 is addressing this bug. I have 10.8.5 on another Mac with FileVault and Guest activated, and it works fine.