Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

KieranDotW

macrumors 6502a
Original poster
Apr 12, 2012
624
69
Canada
Hi,

I have a 2tb Seagate External HDD divided into two 1tb expansions for backups and external storage, respectively. As of a few days ago I have been able to mount and access the external storage partition; however the backup partition does not mount.

As a last ditch effort I'm considering reformatting the drive since I managed to retrieve everything I needed from the external storage partition. However, Disk Utility doesn't respond whenever I launch it - I'm met with a blank window which reads "loading disks", which continues for as long as 20 minutes or until I give up and force quit Disk Utility. That being said, I can't use Disk Utility to mount or reformat the partition.

Is there any other method/utility I can use to mount or reformat the disk/partition? Thanks.

pUjvMT6.png
 

Kissmyne

macrumors 6502
Apr 21, 2015
354
48
Yes, you can utilize the diskutil command in Terminal. Launch terminal and type "man diskutil" which will give you a complete guide to how to use the tool
 

KieranDotW

macrumors 6502a
Original poster
Apr 12, 2012
624
69
Canada
Yes, you can utilize the diskutil command in Terminal. Launch terminal and type "man diskutil" which will give you a complete guide to how to use the tool
Not much luck there either
When I use the mountDisk command, I receive the message "One or more volume(s) failed to mount"
When I use the repairDisk or verifyDisk command, I receive the message "Unable to repair this whole disk: A GUID Partition Table (GPT) partitioning scheme is required (-69773)"
When I use the partitionDisk command, I receive the message "Error: -69888: Couldn't unmount disk"
When I use the eraseDisk command, I receive the message "Error: -69888: Couldn't unmount disk"
 

KALLT

macrumors 603
Sep 23, 2008
5,380
3,415
Try ‘diskutil unmountdisk diskX’ (substitute the X with the disk number). If that does not work, try ‘diskutil unmountdisk force diskX’.

Then retry the erasedisk command.
 

kschendel

macrumors 65816
Dec 9, 2014
1,310
591
I'd question why you want to do anything with the drive at all. If you reformat it you won't be able to retrieve anything from either partition (I know you said you got what you needed from the ext-storage partition.) Given that it's already caused problems, I sure wouldn't trust it for backups.

It's possible (although IMHO somewhat unlikely) that you have an enclosure fault. If you have another enclosure that will fit the drive, maybe try in that one to see if it works any better. Otherwise, if it were me I'd just toss it into the trash, or send it back to Seagate and see if they'll replace it for you. (I once managed to get a replacement external drive from WD after one died a few months out of warranty, so one never knows.)
 

Fishrrman

macrumors Penryn
Feb 20, 2009
29,279
13,378
Some questions:

In your first post, you said the drive has 2 partitions.

You said you "managed to retrieve everything I needed from the external storage partition".
So you could afford to sacrifice that partition if required -- right?

You said the second partition was a "backup".
Do all the things that are backed up on that partition "exist" elsewhere?
In other words -- if you erase the "backup" can you start over, creating a new backup?

If the answers to all the questions above are "yes", then I suggest you just re-initialize (erase) the drive and start over.

Have you tried taking the drive to a DIFFERENT COMPUTER and connecting it?
To see if it would mount there?
If it does, have you tried re-initializing it there?
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.