Time Machine Won't Back up anymore to External HD

[brownize]

My Back-up to an External HD hasn't worked for 63 days. The pop up says:

Time Machine couldn’t complete the backup to “WD Ext HD "Time Machine Backups".

The backup disk could not be found. Make sure the backup disk is connected or select a different backup disk.

It IS connected via USB.

I ran Disk Utility and got the message: "First Aid process has failed. If possible back up the data on this volume. " Problem 69842 occurred while restoring the original mount state. File system verify or repair failed. -69845). Operation failed." It also shows the Ext HD is "Not Mounted", with 999.86 GB Capacity, -- Used, and Zero KB Available.
macOS can’t repair the disk “WD Ext HD "Time Machine Backups"”.
"You can still open or copy files on the disk, but you can’t save changes to files on the disk. Back up the disk and reformat it as soon as you can."

IMac 2020, OS Ventura.

Suggestions please. Thanks!

 

[gilby101]

1) In Terminal do diskutil list just to make sure you know the device numbers. Look for the volume under Name and note the Identifier (something like disk3s2). Then do diskutil verifyVolume disk3s2 but with the Identifier for the TM volume. What are the results of that? It may tell us the error which led to the -69845.

2) Is the disk used only for TM?

3) Does it mount, if only read-only? I am guessing not.

4) If it does mount, how full is it? If not, are you confident it is sufficiently large for your TM backup?

5) Until this is sorted out (and you may need to discard the disk), get another large enough HDD and start a new TM backup.