I tried using disk utility both in the regular mode and recovery mode. I tried using the terminal and this is what I get:
MBP2011:Volumes admin$ diskutil repairDisk /dev/disk2 Repairing the partition map might erase disk2s1, proceed? (y/N) y Started partition map repair on disk2 Checking prerequisites Checking the partition list Adjusting partition map to fit whole disk as required Checking for an EFI system partition Checking the EFI system partition's size Checking the EFI system partition's file system Checking the EFI system partition's folder content Problems were encountered during repair of the partition map Error: -69854: A disk with a mount point is required
This external hard drive has a lot of information I don't want to lose, does anyone else know what I can do?