It doesnt need to be formatted..you just hook it up and you can go in and delete all the recordings, perhaps it might n evebe best to do a reset everything after its up and running, that will clear the drive. Remember that connecting that drive replaces the internal drive, so all SL's and settings will need to be set back up. If you want to erase it on your Windows based pc you need to use disk management and delete the partitions, it uses the xfs linux file system so it won't be recognized by any Windows OS. But the disk should be recognized by computer and you can access the drive through disk management.