External TimeMachine HDD visible in Terminal diskutil list but not in Disk Utility

[BenjaminMoore]

The external HDD I use for my TimeMachine backup is suddenly not mounting or even showing up in Disk Utility.
But when I try diskutil list in Terminal it seems to be there.
Any hints on how to mount this so I can restore from backup?

/dev/disk3 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *6.0 TB     disk3
   1:                        EFI EFI                     209.7 MB   disk3s1
   2:                  Apple_HFS 6TB TimeMachine         6.0 TB     disk3s2


Benjamins-iMac:~ benjaminmoore$ diskutil info disk3
   Device Identifier:         disk3
   Device Node:               /dev/disk3
   Whole:                     Yes
   Part of Whole:             disk3
   Device / Media Name:       HD-GDU3


   Volume Name:               Not applicable (no file system)
   Mounted:                   Not applicable (no file system)
   File System:               None


   Content (IOContent):       GUID_partition_scheme
   OS Can Be Installed:       No
   Media Type:                Generic
   Protocol:                  USB
   SMART Status:              Not Supported


   Disk Size:                 6.0 TB (6001175126016 Bytes) (exactly 11721045168 512-Byte-Units)
   Device Block Size:         512 Bytes


   Read-Only Media:           No
   Read-Only Volume:          Not applicable (no file system)


   Device Location:           External
   Removable Media:           Fixed

   Virtual:                   No


Benjamins-iMac:~ benjaminmoore$ diskutil info disk3s2
   Device Identifier:         disk3s2
   Device Node:               /dev/disk3s2
   Whole:                     No
   Part of Whole:             disk3


   Volume Name:               6TB TimeMachine
   Mounted:                   No


   Partition Type:            Apple_HFS
   File System Personality:   Journaled HFS+
   Type (Bundle):             hfs
   Name (User Visible):       Mac OS Extended (Journaled)
   Journal:                   Unknown (not mounted)
   Owners:                    Disabled

I tried repairDisk, but got this:

Benjamins-iMac:~ benjaminmoore$ diskutil repairDisk /dev/disk1
Repairing the partition map might erase disk1s1, proceed? (y/N) y
Started partition map repair on disk1
Checking prerequisites
Problems were encountered during repair of the partition map
Error: -69808: Some information was unavailable during an internal lookup

This external disk appears to have coincidentally died on the same day as my internal fusion drive, and is the only backup I have. Can anyone help?

 

[HDFan]

There are a number of 3rd party disk utilities ($) which can sometimes repair a disk. DiskWarrior, Techtools Pro ...

Hopefully you will get it working. Then follow the backup rule of 3 backups on 3 different media types in 3 different locations if possible. One off-site, such as in a safe deposit box.

 

[BenjaminMoore]

Is it worth it to try to move the HDD to another enclosure?

 

[HDFan]

This external disk appears to have coincidentally died on the same day as my internal fusion drive,

Happens, but might also point to the problem.

Is it worth it to try to move the HDD to another enclosure?

If you put your ear to the drive does it spin up? Any clicking noises? Can you try to read it attached to a different computer? If you have a different enclosure worth trying.

 

[BenjaminMoore]

It's definitely spinning, and I don't hear any clicking. I don't have another computer handy so I can't test that at the moment.
I've never actually opened one of these enclosures, but since these are my only copies of several of my files I'm a little desperate and willing to try anything at this point.

 

[Significant1]

Have you enabled all devices in disc utility (cmd+2)?

 

[BenjaminMoore]

Have you enabled all devices in disc utility (cmd+2)?

I hadn't tried that, but no luck.

Doesn't the fact that diskutil list sees a 6TB drive with an Apple_HFS partition mean the disk is still physically OK?

Even the "system report" on "About This Mac" can see the disk:

6TB TimeMachine:
  Capacity:    6 TB (6,000,831,152,128 bytes)
  File System:    Journaled HFS+
  BSD Name:    disk1s2
  Content:    Apple_HFS
  Volume UUID:    26AD678F-0983-34A5-8E06-3351E9427FB6

Why would Disk Utility still be unable to see it?

 

[Fishrrman]

I know this advice doesn't help at this moment, but it WILL help in the future.
(there he goes again, like some old broken record!)

STOP USING time machine.
Use either CarbonCopyCloner or SuperDuper instead.

If you had been using either, I reckon you wouldn't be having the problems you're having right now.