Trouble with external hard drive for Time Machine not recognised in Disk Utility

If the drive has failed, it's failed and needs to be replaced.

You shouldn't have to erase it if it's failed. A warranty is not predicated on a user action like that. If the drive is bad, the seller should honor the warranty. How would the seller even know? Failed is failed and if he attempts to read it well ... it fails.

Justanothergeordie wrote:

Thanks for the reply. If I run FA from the bottom up, then:

– Volumes takes a while but is always okay

– Containers comes up with an error first after running a check quite quickly, then if I run it again it takes longer but is fine

– Device runs quickly and is always okay

I'm still at a loss if something's wrong somewhere on the disk or maybe the cable...?

The disk has already failed (at least once) and now you cannot get a repeatable clean run of Disk Utility First Aid. You should replace the drive. You can certainly try a new cable, but I doubt that is the problem.

When MacOS detects problems with an external drive, it will automatically run fsck (which is essentially the same as Disk Utility First Aid) on that drive, which can take a long time. After fsck completes, the disk may mount. However if the file system was not repairable, the disk may still have problems.

It sounds like this is going on with your drive. You can repeatedly reformat it, but you have already done that and errors return. This means that the device is not reliable and certainly should not be relied on for backups, which need to be bulletproof.

You need to run First Aid from the bottom up, Volumes, then Containers, then the device.

Was the error repaired?

When the drive didn’t show up and you could feel it spinning, was it spinning up, then quiet, then spin up, repeating that cycle? If so, it was demanding too much current from the USB port. They all tend to do that when they get older.