So says the message in Disk Utility. This a 3TB Seagate GoFlex FireWire\nwith a one-TB partition for general use and a two-TB partition for Time\nMachine backups. 27-in. late model iMac with latest Mac OS, etc.\n\nTime Machine began reporting back-up failures after 24 April. I turned\noff TM because I have other backups of my internal drive (SuperDuper)\nand I didn't have time to deal with the issue earlier.\n\nThe TM partition passed the First Aid routine with no errors. Since\nnothing else worked to get Time Machine working on this partition I\ndecided to start anew with it by erasing it. The error message tells me\nthat ³Volume Eras failed with the error: Mediakit reports not enough\nspace on device for requested operation.²\n\nIn fact, the disk has 1.25 TB used and 745 GB available. It seems to me\nthat the disk ought to be erasable.\n\nIdeas welcome.\n\nTIA!