Time Machine files cannot be erased I put Mavericks on my iMac and Time Machine quit updating.  I just want to erase all the TM files on the external HD, but cannot.  Looks like reformating is the only answer. Any solutions? Using SuperDuper! now.
Deleting Time Machine backups can take a very long time, since they can contain hundreds of thousands of files. Moving the files to the trash can take a long time, emptying the trash can take a long time, and using command line "rm" commands can take a long time. By long time I mean tens of hours.

Usually the fasted way to remove such numbers of files is to use Disk Utility to erase and/or reformat and/or repartition the drive. Copy anything you don't want lost off of the drive, reformat it, and start the TM process again.