In all likelihood, the Ki Pro produced a "Backup and Reformat" prompt due to a directory error on the disk. You could have connected the Ki Pro Storage Module to a Mac, backed up the files by copying them, and then reinserting the Storage Module in the Ki Pro and formatting via the MEDIA menu.
If you are having trouble reading the drive in the Ki Pro, you should consider contacting AJA Technical Support for assistance. They can be reached via phone or email free of charge.
AJA Video Systems
+1 (530) 274-2048 Intl.
(800) 251-4224 US