The disk I was using for TM was getting flakey, so I got a new one. First time machine backup was 440 GB, and not surprisingly, it took days to run through. That's fine. Then time machine decided to do it all over again. Days later, it finally finished the second complete backup, and now 1 TB of my new 3 TB drive is taken up with effectively one backup. It then sat for two days in "cleaning up..." phase. I let it run interrupted, hoping it would free up some of the extra space it was using. No such luck. Now today, it has been sitting for hours on "Backing Up: 6 KB of 5.51 GB". My brain says, ignore it and let it do it's thing. Maybe in a week or two it will have settled down. But... Oh how I don't love Time Machine!!