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Question: Time Machine's Warning - Identity of the backup disk changed

Good evening to everyone,

today I've got this pop-up window from Time Machine:

User uploaded file

Anybody knows what does it mean???

Of course I have not erased or replaced the disk. So mainly I'm asking, do I have to worry that really "someone may be trying to trick my computer into backing up to the wrong disk?" If so, one should have got access to my Time Capsule's Wi-Fi, but I'd say I'm using pretty strong WPA2 key also I have checked Wireless Clients list for unknown hosts, I haven't seen any, I can easily identify all of them.

Thanks in advance for help, some info or explanation, have good evening everyone,


iMac with Retina 5K display, macOS High Sierra (10.13.3), iMac17,1 Fusion Drive

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Question marked as Solved

Mar 11, 2018 4:41 PM in response to Manolis_from_Prague In response to Manolis_from_Prague

That message will occur for a number of legitimate and mundane reasons. For example, a change in your network configuration, or another disk with the same name as the TM's backup disk was connected to your Mac (macOS has to assign new identities to keep them separate) are two that come to mind. The same message will occur if you were to delete the sparsebundle disk image on the Time Capsule, for whatever reason you might have wanted to do that.

  • If you are certain that no one tampered with your Time Capsule, then select Use This Disk.
  • If you are not certain, select Don't Back Up. Then, use Time Machine's Preferences and remove it. You can re-select that same backup disk again and backups will continue as they always have.

Mar 11, 2018 4:41 PM

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Mar 11, 2018 4:48 PM in response to John Galt In response to John Galt

Actually, at that time when I got this warning, I just selected Don't Backup, because I were really not sure what's going on. But what happened... after next Restart of my iMac, everything solved just by it self... surprisingly, without any of my interference. I didn't change anything, but the warning for now is gone and Time Machine Backups continues as normal.

Thanks anyway for explanation, even it's still a bit of mistery why it had happened.

Have good evening, bye bye.

Mar 11, 2018 4:48 PM

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User profile for user: Manolis_from_Prague

Question: Time Machine's Warning - Identity of the backup disk changed