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How to free space on full Time Machine external drive?


Prominent Member
My 320GB external hard drive that backs up my iMac, running Lion, is showing as full in Time Machine and Time Machine doesn't seem able to delete an older backup to free space for the latest backup. The backup requires 66GB of space but only 14GB is available.

Is there a way I can manually delete an earlier backup or do I have to reformat the drive?

I was thinking of just buying a higher capacity drive but I'd rather save some money, and, to be honest, I've been backing up things that I didn't really need - i.e. things other than my Documents, Pictures, Music and Videos folders.



Prominent Member
I've just discovered how to do this.

In the Time Machine screen (where you scroll through the backups), click on the 'gear' icon above 'Action' and select 'Delete all backups of .....'

I deleted all backups of movies and iTunes music, as they don't hold any sentimental value for me.

I then went into Time Machine Preferences and added my Movies and Music folders to the 'exclude from backup' list.

Just incase anyone else in my position wasn't sure how to do this.

I've discovered that I really ought to have another external drive for a monthly clone of my hard drive - using something like Carbon Copy Cloner.

If my whole drive was to go down, it'd take ages to get everything set up again.
Last edited:


Distinguished Member
Someone mentioned on this sub-forum that a true backup needs at least two different physically-located copies of any given file (my own attempt at interpretation).

IMO, your 320GB external HDD is far too small for such purposes.


Prominent Member
I've just read on the Apple support page that you're supposed to have another backup in another building and in the Cloud (e.g. using Dropbox).

I know I'll be taking a risk but I'll just be keeping my two external hard drives in my bedroom next to my computer. :rolleyes:

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