Source : MacosxhintNot everyone uses Time Machine, however every time you attach an external Firewire or USB disk, the program proposes to use that disk as a backup volume. If this happen rarely, then it is not a problem, but if you have a portable to which to often connect a disk, it becomes annoying. To suppress this notification, all that is needed is to enter the following command in the terminal:
defaults write com.apple.TimeMachine DoNotOfferNewDisksForBackup -bool YES To return to the previous condition, one just reenters the above line but changing the YES to NO.
It is high time for Apple to add this configuration options to what is one of best the innovations of Mac OS X.
[translation by crispin]
