How to remove external data disk from Time Machine backup on MacBook Air M4?

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Level 1

105 points

How to remove external data disk from Time Machine backup on MacBook Air M4?

MacBook Air M4, Sequoia.

Can't delete data disk data (not the Mac boot drive but an external data disk's data) from a TimeMachine backup.

I see Apple has removed the "delete" option when perusing the "warp drive" TimeMachine backups. I have an external disk that was backed up using TM (in addition to the internal HD) but, now that I needed to replace that external with a larger one, I can't see any way to remove that drive's data (and its icon) from the TM disk in order to start using the new drive. In fact, I don't even see any way to "unexclude" this new HD as it doesn't show up in the list of drives to "exclude". The old external HD, as well, doesn't show up in the list of drives to exclude.

Do I just need to reformat the TM drive and start over? I should also mention that my external HDs (all APFS-formatted) seem to "self-exclude" themselves from my TM backup attempts and don't appear in the "exclude" Options.

Should I just go back to Carbon Copy Cloner and abandon TM? Thanks.

[Re-Titled by Moderator]

Posted on Nov 30, 2025 10:44 AM

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Answer 1

VikingOSX

Level 10

123,144 points

Nov 30, 2025 11:52 AM in response to Barry Levine

You cannot delete Time Machine data from an APFS formatted drive. That is a fact, not a suggestion.

You perform a final backup, label it with that backup date and the version of the operating system and then set that drive aside. You do the preceding before you upgrade to Tahoe, and then start with a new APFS-formatted Time Machine drive that is 2- 3x the capacity of your internal drive. This is what I do with every major operating system upgrade.

I have never attempted to boot into Recovery and then use Disk Utility to reformat an existing APFS-formatted Time Machine drive. Sounds simple but probably is not. Even after an upgrade, I prefer to keep the old TM drives around for awhile as there may be data on them that is no longer on my Mac.

I also have macOS Monterey, Sonoma, and Sequoia guests in Parallels Desktop Pro on my M4 Mac Mini Pro. I used their respective Time Machine drives with Migration Assistant to populate those guests after the clean guest operating system installation.

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Answer 2

Dec 1, 2025 5:05 AM in response to Barry Levine

FWIW, I would just reformat the drive you want to use for Time Machine. Generally any drive that you reformat you will end up with a prompt that asks if you want to use as a Time Machine Drive depending on its size.

Remember, Time Machine's purpose is not for archiving data but a means to recover your system from a previous state or restore files that my be accidentally deleted or perhaps work in progress files where you may want to roll your work back to a few days ago and start over.

Personally, I believe that one back up is no backup at all since the backup device can fail. My approach is a Time Machine backup on one drive and a Carbon Copy cloner backup on a second drive. Having two separate backups and also backing up by two different methods adds a bit of safety to the data.

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Answer 3

Barry Levine Author

Level 1

105 points

Dec 1, 2025 8:12 AM in response to woodmeister50

@woodmeister50 - After my original post, I did a re-think and came up with a plan that's similar to what you've suggested. I'll use TM for my internal SSD (which seems to be TM's preference in my experience) and FreeFileSync (FFS) for the external SSD (which has only data, no system). Then I'll do an additional set of FFS backups (mirrors with some versioning) to two folders on a third HD. The result of all this will be two backup sets...and a good night's sleep.

Thanks for your thoughts.

Barry

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Answer 4

Dec 1, 2025 12:51 PM in response to Barry Levine

Indeed, an often recommended strategy is 3-2-1, meaning 3 copies of your data, two of which are backups and one of which is stored offsite.

Personally, I have a local NAS as my primary backup and a pair of SSDs that I connect weekly and swap offsite as my secondary backups (and since my NAS is RAID1, technically I have 5-4-1 but I don't mind the overkill).

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