Killing Time Machine

The nature of on-set data management means you are constantly reformatting and mounting drives. Each time a drive is reformatted, Mac OS X Snow Leopard doesn't have a record of that drive, and thinks the it is "new." This initiates a dialog box, asking if you want to use the drive for Time Machine. Once or twice, and this is just an annoyance, but after formatting fourteen drives/day, six days a week, for five weeks.... you kind of want to build a real time machine so you can get all those wasted minutes of your life back. Seriously, those seconds add up.

Turning Time Machine OFF in the System Preferences isn't enough. This dialog box will keep popping up. In order to truly kill Time Machine you must use Terminal.

You get extra points if you open Terminal with Quicksilver.

Open Terminal, and type: 
defaults write com.apple.TimeMachine DoNotOfferNewDisksForBackup -bool YES


press Enter.

Ta da! No more nagging questions from Time Machine!

via Mac OS X Hints