|Reread your post. I assume you mean you formatted to NTFS or FAT32 and it then reverts to RAW. Is that correct? |
If so, that is most likely caused by improperly disconnecting the external drive. You should always use the safely remove Icon in the tray by the clock to disconnect the drive before shutting off or pulling the cables.
If you have data on the drive you want to save you can probably fix the partition.
This assumes there is nothing wrong with the drive in the first place.