How to reset time machine

Thanks.I also wanted to fully erase my old backups and start with a brand new one. So did as you suggested and it seemed to work....except, when I now turn on Timemachine and start a new full backup, the time capsule still seems to show that the space taken up by the old back ups, hasnt been frred up. ALmost like the old backup is still there....but hidden. A puzzle.

Please visit Pondini's Time Machine FAQ for help with all things Time Machine.

Here's the easy way:

Drive Preparation

1. Open Disk Utility in your Utilities folder.

2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Click on the Partition tab in the DU main window.

3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Click on the Options button, set the partition scheme to GUID then click on the OK button. Set the format type to Mac OS Extended (Journaled.) Click on the Partition button and wait until the process has completed.

Yes using a time capsule. A starting the erase via Airport utility. The only partition I have is the one on the time capsule that was set up yesterday when I tried the Drive Prep routine. I'll let the erase go ahead and then do a full back up. Takes ages over WiFi I know.

See A #4 Here > http://pondini.org/TM/Troubleshooting.html

Then you did not actually erase the drive. Are you using a Time Capsule? If you are, then you need to erase the drive via Airport Utility.

Do you have a partitioned drive?

My instructions do not apply to erasing a Time Capsule. Follow the instructions via Airport Utility's help.

Understood. And thanks for the help.