The automatic back up function will delete the oldest stored data on your time machine automatically to make room for the latest back up data.
That's the theory. In practice, this rarely works reliably unless you have a very small incremental backup.
Otherwise, you will see a message that the backup is too large and Time Machine cannot back it up. That is likely what chrissice is seeing as well.
Thanks for the suggestions.
I'm using Mac Os X 10.6.8
I get a message saying the back up of 250g is too large. There's only 70g left...
I'd like to clear out all the old data and start again now I've cleaned off the large video files from my mac.
ANy suggestions as to what I should do. I'm a little lost?!
interesting. It works for me. But erasing content from a disk is easily done using the app "Disc Utility".
However, I am not sure whether your version of OS X has it installed.
If you have it and when you open it, it shows on the left panel all the disks that are available.
Chose your back up disk and go to the tab "Erase". You can even chose from the "security options" how "complete" in terms of recovery the content should be erased. Usually, the default is enough.
Then click on erase and you will find all content gone from the disk you marked on the left panel.
Disk Utility is not used to erase the Time Capsule hard drive.
Open Macintosh HD > Applications > Utilities > AirPort Utility
Click on the Time Capsule\, then click Manual Setup
Click the Disks icon at the top of the window
Click the Disks tab just below this
The Quick Erase option will be fine for your needs and will only take a minute or two
It is strange that disk utility is missing.. but it is not usable anyway.. The TC (I presume what you mean by Time Machine) is a network drive. Disk Utility only works with local drives.
You open the airport utility and go the disk page and click the erase.. use only a quick erase otherwise it takes forever.