I use my Mac in a multi OS environment (i.e. with Windows) and whenever I take a screenshot (Cmd-Shift-4) intended for a PC user, I have to go to information and tell the OS not to hide the extension ...

A: A few weeks back, one way I suggested to protect yourself from unleashing a virus is to be weary of unknown file types. I recommended to not open unknown files with the following extensions: .exe, ...