How to delete old Time Machine backups with permission errors on an external drive?

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Level 1

4 points

How to delete old Time Machine backups with permission errors on an external drive?

I use an external drive for Time Machine backups, which is almost full (10% free). I didn't think it should be full. I started digging and found that almost 1.5 TB of storage is used by Time Machine backups from 2019. Time Machine does not recognize them - only backups since 2024 are recognized. I'm not sure why this happened, but the old backups are not needed. I am needing a method to delete the old files. I am getting permission errors , I cannot find a way to delete them. Here are the ways I have tried:

1) Delete and Command-Delete

2) Drag to Trash

3) Terminal - tmutil

4) Terminal - rm

The various error messages indicate permission issues. My account is an admin equivalent. Any ideas?

[Re-Titled By Moderator]

MacBook Pro 14″

Posted on Mar 14, 2025 2:13 AM

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Answer 1

Barney-15E

Level 10

122,300 points

Mar 14, 2025 4:40 AM in response to wg3067

There is no way to manually delete backups in any way.

If your TM drive is full, either erase it and start over or get another drive (this time larger) so you can keep the older.

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Answer 2

Owl-53

Level 10

103,141 points

Mar 14, 2025 2:32 AM in response to wg3067

Time Machine Backup Utility has marked the destination Drive a Read Only

Attempting to modify, alter or otherwise cherry pick TM Snapshot for deletion will or may corrupt All the backups

It appears " Time Machine does not recognize them - only backups since 2024 are recognized " is because the TM Backup History was inherited

It is suggested that you set aside the Existing Drive for future purposes or safe keeping

Back up your Mac with Time Machine

Use a storage device with at least twice the storage capacity of your Mac. For example, if your Mac has 1TB of storage, your backup disk should ideally have at least 2TB of storage. If Time Machine needs more storage space, your Mac will let you know.
Use your Time Machine backup disk only for Time Machine backups, not for storage of other files.*

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Answer 3

wg3067 Author

Level 1

4 points

Mar 14, 2025 3:16 AM in response to Owl-53

I appreciate the answer, thou I am not thrilled with the suggestion that I purchase a new drive for backups when the current drive works perfectly well for what I need and I don't need a duplicate. I did use Migration Assistant when this MB Pro was purchased in 2023. Curiously, no backups from 2023 exist which probably means TM is working properly now. It's frustrating that there isn't a simple solution to deal with orphaned folders and files.

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Answer 4

Owl-53

Level 10

103,141 points

Mar 14, 2025 3:25 AM in response to wg3067

wg3067 wrote:

I appreciate the answer, thou I am not thrilled with the suggestion that I purchase a new drive for backups when the current drive works perfectly well for what I need and I don't need a duplicate. I did use Migration Assistant when this MB Pro was purchased in 2023. Curiously, no backups from 2023 exist which probably means TM is working properly now. It's frustrating that there isn't a simple solution to deal with orphaned folders and files.

You are welcome

OP Wrote " I use an external drive for Time Machine backups, which is almost full (10% free). "

Then and presented in a helpful manner.

What is the issue with 10% free " when the current drive works perfectly well for what I need " ?

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