Time Machine has stopped backing up

[Soundhound]

My wife uses time machine on her macbook pro running mountain lion, backing up to a 320 gig external drive. It says there are only 20 gigs available and it needs 30 to continue to back up. It's been doing this since June - she only just noticed this.

I thought Time Machine would fill up a hard drive, more or less, and when it runs out of room, will start to erase the oldest backups. Is that not the case? Can you run out of room on a disk with Time Machine. Or is there a setting we can use to allow it to continue to back up?

thanks.

 

[Macman45]

It is in theory supposed to behave as you describe, but it may work differently with third party HDD's although I have never heard of this being an issue.

What make is the HDD you are using with TM, and how is it connected?


I have an Apple Time Capsule and it deletes older backups when full, just as you describe.

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Additional setup and configuration instructions here, you may have set TM up differently:
http://support.apple.com/kb/HT1427

 

[macinhand]

I had the same issue which was driving me mad and after a quick call to Apple they found the issue to be caused by one of two things listed below!

I use TimeMachine to back up to 320GB WD external drive via USB cable.

1; I had a MacBook Pro of which i was using the above external drive as my back up source! I then purchased an iMac to which i used the external drive to set up the new iMac! This is where Apple found the issue arose! After the new iMac was set up and i carried out the initial back up of the iMac it should have deleted all traces of any back up from a previous machine but in my case it didn't thus leaving certain back up's from the MacBook Pro and the subsequent back up's from the iMac! Then when it came time for the TimeMachine to start deleting the oldest back up's as the drive was full it couldn't as the oldest back up's were assigned to the MacBook Pro which lead to the process to stall.

2; I also had a corrupt back up in the iMac part of things which could give the same symptoms once the drive was full.

The guy from Apple helped me delete the offending back up's and since then all has been fine!

I don't know if you have had a similar situation to mine but at least it will help you eliminate a few situations that can occur.

HTH