Huge Backups.backupdb folder on the same local drive

Question

I recently noticed that my newly installed local disk is running out of space on High Sierra. After some investigation, I found a Backups.backupdb folder that was taking up a significant amount of space on the disk. I was surprised to find multiple backups of the same disk in the folder, even though I had never selected this disk as a Time Machine backup drive.

When I ran the tmutil listbackups command in Terminal, it did not list the backups on the local disk, indicating that they are ownerless and essentially useless. However, I encountered an issue when attempting to delete the Backups.backupdb folder.

I am unsure why this situation occurred and would appreciate any insight or suggestions. Also I would like how to delete the Backups.backupdb folder and free up space on my local disk in the most sure and secure way.

Answer 1

Why aren't you allowed to delete the Backups.backupdb folder?

The Backups.backupdb folder is protected by the system and is therefore extremely hard to delete (as well as any of its contents) through normal deletion means (e.g. Drag it to trash or select and press cmd+delete).

You could normally run sudo rm -rf Backups.backupdb to delete this folder but as mentioned above, it won't work and normally show that error message (at least for me) :

Operation Not Permitted

How to fix that error? (And delete the folder)

Based on this old answer, to delete the Backups.backupdb folder, run this command in Terminal :

sudo /System/Library/Extensions/TMSafetyNet.kext/Contents/Helpers/bypass rm -rfv Backups.backupdb

This will bypass every restriction that are in place causing it to show the error shown above ("Operation Not Permitted") when running sudo rm -rf Backups.backupdb.

Note that "bypass" is still located in /System/Library/Extensions/TMSafetyNet.kext/Contents/Helpers/bypass for me.