• To do it properly: Partition the drive using Disk Utility and assign one of the partitions as your backup and the other as you "transfers" partition (use OS Extended as the format unless you plan on mounting the drive on a PC too).

    To do it easily: Although the drive will be indexed by Time Machine which reads/writes to the one folder within it, you can still drag/drop to the disk as normal (avoid naming/touching the one existing folder in there AT ALL).

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