When windows is doing a backup, is it safe to play a steam game?

[destructor_rph]

Will it screw up the backup?

 

[photonboy]

It's perfectly safe.

It may cause some stuttering depending on your CPU, the game and what priority the game and backup utility are set to. For example, a "LOW PROCESS" is ideal for the backup so if your CPU is needed it won't affect a "HIGH PROCESS" which your game is hopefully set to.

I've had backup kick in when I'm gaming. No issue. It's never affected my experience for any game (i7-3770K + GTX680).