I'm using Time Machine for backups of my 500 GB startup disk to a 1 TB external hard disk. I noticed now that the Time Machine backups are at least since days (if not weeks) more than 60 GB big - even if hardly anything has happened on the Mac. Yesterday night Time Machine showed a remaining time of 6 hours for this backup and I left the machine running without going to sleep. This morning Time Machine shows that it started some time ago again with a 60 GB backup, showing the remaining time with 18 hours. I believe that this is going on since quite a while because I have since quite a while the impression that my computer is much too often slowed down by some background process. I am making another backup with Carbon Copy Cloner once a day, and this backup usually need less than 30 minutes to complete. I think something is very wrong with the Time Machine backup. I guess that the only thing I can do is to stop the Time Machine backup, erase the disk, and start fresh. Does anybody else had this happen, too? Is there another possibility to fix this other than stopping, deleting and starting fresh again?