WD Elements Portable EHD Suddenly Won't Backup Mac: "Not Mounted"

The WD Elements Portable WDBUZG0010BBK - 05 EHD that my wife and I have used to backup her iMac or my MacBook Pro for at least several years suddenly stopped working last week.

Apple support told my wife that the EHD had to be replaced. However, after checking various support articles on the WD website, I’m not so sure. When I use Disk Utility to check the EHD, it says “Not Mounted…999.83 GB capacity…Zero KB available…’- -’ used…disk4s2 disk.”

Per your website, perhaps the EHD needs to be repartitioned and/or reformatted?

I also read that sometimes another app is very active and interferes with the WD EHD backups. Last week I had connected our two iPhones and my MacBook Pro to iCloud and set up iCloud Drive for the first time — right about the time the EHD stopped backing up. (My wife never set up iCloud Drive on her iMac.) So I disabled all iCloud, iCloud Drive, and iMessage functions on my MacBook Pro and our two iPhones, before trying to get the EHD to start functioning again. Doing so made no difference. Still getting the same Disk Utility readings.

I then installed WD Drive Utilities, to check the EHD. However, when I open the app, I receive a message, “Attach a supported WD drive.” When I dragged the “1TB WD” label from the left-hand sidebar in Finder into the WD Drive Utilities dialogue box, the EHD disappeared from the sidebar. I was only able to locate it through Disk Utility, but the utilities’ dialogue box still showed the same message. How do I get Utilities to “attach” the EHD, which sometimes appears in the sidebar and sometimes does not.

Can I get the EHD to resume Time Machine backups, or do I, in fact, have to replace the drive?

Regarding my post yesterday, here is the information I see when I click on the “Info” icon in the Disk Utility reading of our “Not Mounted” WD Elements EHD. I hope this information is helpful, in terms of answering my question.

Volume name : 1TB WD
Volume type : Physical Volume
BSD device node : disk2s2
File system : Mac OS Extended (Journaled)
Connection : USB
Device tree path : IODeviceTree:/PCI0@0/XHC1@14
Writable : No
Is case-sensitive : No
File system UUID : 605B2A42-F950-3750-8349-31A441088FC8
Volume capacity : 999,826,612,224
Owners enabled : No
Is encrypted : No
Can be verified : Yes
Can be repaired : Yes
Bootable : No
Journaled : No
Disk number : 2
Partition number : 2
Media name :
Media type : Generic
Ejectable : Yes
Solid state : No
S.M.A.R.T. status : Not Supported
Parent disks : disk2

I have precisely the same problem. @Robert_Kenny, did you ever find a resolution? Anyone else got any advice?