Having trouble deleting old Time Machine backups on late 2012 iMac

[Samelson03]

I'm a Time Machine noob. I understand what it does but nothing beyond that, lol. Also, when it comes to the type of stuff i'm having trouble with, i'm also a noob. I'm trying to delete old backups to make room for new ones but I keep getting an error message saying, "Some files can't be processed, either because you don't have permission to modify them, or because they are on a locked volume." What do I need to do in order to delete the back up?

 

[nambuccaheadsau]

Littered with pitfalls TM generally and what you are doing in particular. Suggest giving cloning software, SuperDuper or CarbonCopyCloner, a trial and each has a demo offer.

 

[chabig]

I'm trying to delete old backups

Never do that. Time Machine takes care of itself. It automatically deletes the oldest backips when it needs space.

 

[mbosse]

Never do that. Time Machine takes care of itself. It automatically deletes the oldest backips when it needs space.

This. Let TM do its job.

One question though: @Samelson03: you are referring to an external drive with the backups, correct? When mentioning 'old backups' do you refer to backups of other machines or older backups of your own iMac?

Magnus

 

[briloronmacrumo]

It is possible to use tmutil from Terminal.app to delete TM backups. Depending on which macOS you're running, Terminal.app will require "Full Disk Access" permission via System Preferences/Privacy. I'm not convinced manually deleting is more effective than letting TM manage the backups but it is possible. My recommendation is to let TM manage but for those willing to accept responsibility here is one example:

From within Terminal.app issue:

tmutil listbackups

Resulting in this example output:
/Volumes/YourVolume/Backups.backupdb/YourUserID/2020-04-29-071013
/Volumes/YourVolume/Backups.backupdb/YourUserID/2020-04-29-090057

Copy and paste one of those lines into tmutil's delete command like so:

sudo tmutil delete /Volumes/YourVolume/Backups.backupdb/YourUserID/2020-04-29*

followed by entering your admin user's password would delete all backups on April 29th ( the asterisk is a wild card ).

Please note: using tmutil can damage your TM database if not used correctly. Make sure you're adequately prepared ( backups and enough time and education about what you're attempting ) and willing to accept all responsibility for mistakes and any mishaps. What I've posted is *not* a full tmutil tutorial and doesn't provide all the knowledge you might need to accomplish your objectives. It only shows what's possible but is not recommended for TM noobs.