Unable to Mount Time Machine Partition

[KaPOWitsCHRIS]

Last night I upgraded to macOS 10.15.2 and ever since my Time Machine partition on my external USB drive will not mount. It gives the following error when trying to mount it from Disk Utility: (com.apple.DiskManagement.disenter error 0.) also attached a screenshot.

Naturally I want to avoid formatting the drive or partition.

Any ideas?

 

[madrich]

What did you upgrade from?

 

[KaPOWitsCHRIS]

What did you upgrade from?

From 10.15.1

 

[madrich]

Did you try to reset the Time Capsule? There are two types of reset a full and a partial.

 

[jaymacke]

I have EXACTLY the same issue. What did 10.15.2 do to external time machine drives? Should note that I also tried force mounting the volume, which didn't work either.

 

[magmamoz]

I also have the same issue. Upgraded to 10.15.4. My Time Machine drive is first partition on a 2T Seagate hdd with a total of 3. I can access and read/write the other 2 partitions. The Time Machine can not be repaired or mounted by neither Disk Utility or Disk Drill.
Any ideas?

 

[madrich]

I also have the same issue. Upgraded to 10.15.4. My Time Machine drive is first partition on a 2T Seagate hdd with a total of 3. I can access and read/write the other 2 partitions. The Time Machine can not be repaired or mounted by neither Disk Utility or Disk Drill.
Any ideas?

Please note that if your TM files were saved under a different OSX from a new one (ie Catalina) installed on your computer now, you will be unable to read or mount them, like when the same files were backed up under the same OSX. You will need to use the Migration Assistant to procure any TM files. Afterwards you will need to backup your files with the new OSX then the new backup could be read and mounted under the new OSX.

 

[magmamoz]

Please note that if your TM files were saved under a different OSX from a new one (ie Catalina) installed on your computer now, you will be unable to read or mount them, like when the same files were backed up under the same OSX. You will need to use the Migration Assistant to procure any TM files. Afterwards you will need to backup your files with the new OSX then the new backup could be read and mountEd under the new OSX.

Thanks for your input!
I'm aware of the problem of upgrading from earlier version of MacOS. In this case I upgraded Catalina 10.15.4 to 10.15.5 - still Catalina.
I have occasionally seen the error before but always been able to use Disk Manager to repair/fix the problem.
I'm not aware of any new Partition or APFS since Catalina.
However - I have used the same TM disk since 10.14.? - before upgrading to Catalina. DoYou think that this can be the issue; even though TM has been mounting since 10.15.1?
BTW - I have backup of all important files and basically only use TM for system backup. Should I simply reformat the partition under 10.15.5 and start over maybe?

 

[madrich]

The TM is a peculiar animal. If you upgraded and saved the system files to your TM under a prior version of Catalina, I would think that you should not have any problem mounting the TM under the same OSX in a later version. While the TM is open, did you inherit (select) the TM directory file with the prior version of Catalina?

Otherwise, you may want to search other Apple forums for a resolution or start over (erase the TM) as you indicated in your last comment.

 

[magmamoz]

The TM is a peculiar animal. If you upgraded and saved the system files to your TM under a prior version of Catalina, I would think that you should not have any problem mounting the TM under the same OSX in a later version. While the TM is open, did you inherit (select) the TM directory file with the prior version of Catalina?

Otherwise, you may want to search other Apple forums for a resolution or start over (erase the TM) as you indicated in your last comment.

Thanks for your input!

FYI - I received this answer from the Apple Discussions Forum:

Upgraded to macOS 10.15.5 and ever since Time Machine partition on my external USB drive do not mount Erase the partition and start the backups over. If you have a problem, again, get a different backup drive.

The answer seems clear to me - erase and start over!

 

[madrich]

The answer seems clear to me - erase and start over!

That’s the easiest way out!