Connecting a HDD for recording:

If HDD is initially fat32:

Via settings, system settings, storage you have the option to assign HDD, what actually happens is the unit reformats to ntfs, you then have to disconnect and reconnect for it to be recognised again and can then assign to record.

If HDD is initially ext 3:

Same scenario as if fat32.

If HDD is initially ntfs:

You only have to assign it for recording purposes.