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Mounted external disk, Time machine can't 'see' it.

I am trying to back up on time machine to my external ssd hard drive.

I get a message, 'Back up disk not available, Try backing up again when the external HD is available.'


I've run first aid. It is a USB A.

My main internal HD is partitioned. I don't know if that could be an issue. I only want to copy 1 partition, the main HD. The external HD is not partitioned.


I tried 'Restore' with my main drive, unmounted, remounted and rebooted the machine and that failed as well.



Thank you


Mac Studio

Posted on Jun 4, 2023 10:02 AM

Reply
Question marked as Top-ranking reply

Posted on Jun 4, 2023 12:14 PM

See if what has worked for me might work for you.


Format the backup drive in Mac OS Extended (Journaled), aka HFS+


Restart the Mac and check to see if you can select the drive as a backup destination in Time Machine Settings


If yes, go ahead and start a backup. If an error occurs, try again


If Time Machine can "see" the drive, it will automatically......(and probably without telling you).....format the backup drive as APFS (Case Sensitive) before the backup begins, then the backup will run.


Now, if Time Machine cannot even select the drive as a backup destination, then more work is going to be needed.



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12 replies
Question marked as Top-ranking reply

Jun 4, 2023 12:14 PM in response to Oreocracker

See if what has worked for me might work for you.


Format the backup drive in Mac OS Extended (Journaled), aka HFS+


Restart the Mac and check to see if you can select the drive as a backup destination in Time Machine Settings


If yes, go ahead and start a backup. If an error occurs, try again


If Time Machine can "see" the drive, it will automatically......(and probably without telling you).....format the backup drive as APFS (Case Sensitive) before the backup begins, then the backup will run.


Now, if Time Machine cannot even select the drive as a backup destination, then more work is going to be needed.



Mounted external disk, Time machine can't 'see' it.

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