Time Machine keeps trying to use old backup drive

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Level 1

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Time Machine keeps trying to use old backup drive

I recently bought a new external drive for my Time Machine backup. I moved the backup data over with no problem, and everything is working fine on the new drive. The problem comes when I try to use the old drive for anything else. The computer keeps trying to backup to the old drive, despite having a different name and being explicitly disabled in Time Machine. I have even changed the UUID on the old drive, in hopes that Time Machine would not recognize it any more, but that didn't work.

So my question is this: How can I keep using the old backup drive as a generic external drive without Time Machine continuing to try to back up to it?

Posted on Jul 25, 2019 1:54 PM

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Answer 1

Top-ranking reply

fuzzymo

Level 4

2,036 points

Jul 25, 2019 3:01 PM in response to avockley

You probably used this guide to transfer your Time Machine backups to the new drive. Time Machine: How to transfer backups from a current backup drive to a new backup drive - Apple Support.

So if you are sure the transfer was successful, why not just erase and reformat the old drive using Disk Utility. Then you can use it again as you wish.

Before you erase and reformat, as a test, unmount the old drive and see if the new drive still functions properly as your Time Machine backup disk.

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Answer 2

mulberry58

Level 6

10,230 points

Jul 25, 2019 2:21 PM in response to avockley

click on the apple icon at the menubar
click on Preferences
click on TimeMachine
unlock the padlock
Scroll to Add or remove backupdisk
select the external drive you want to remove
click on Remove disk
click on Stop using this disk

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Answer 3

avockley Author

Level 1

8 points

Jul 25, 2019 2:52 PM in response to mulberry58

Unfortunately, the solution is not that simple. When I remove the old disk, it also removes the new one. And when I add the new one back, it also adds the old one. There aren't 2 disks listed as active backup disks, it just picks whichever is connected at the time. It's like Time Machine can't tell that there are 2 different disks.

If I have both drives plugged in, and disconnect the new one, an alert pops up that says "The identity of the backup disk 'Derp 2' has changed since the previous backup".

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Answer 4

avockley Author

Level 1

8 points

Jul 25, 2019 3:08 PM in response to fuzzymo

While I did not follow a guide for the transfer, that is pretty much the procedure I used. I was hoping not to have to reformat the drive, as there is about 2 TB of other stuff on there I want to keep, and copying that around will take quite a while. Plus, it's an odd bug, and I just want to figure out what's going on in the first place. I guess I'll just copy the files to my new drive temporarily and reformat the old one.

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Time Machine keeps trying to use old backup drive

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