Hi guys, here is my problem, I have an Imac 24" and a Mybook external HDD. Ever since Leopard came out Ive been doing backups with time machine, then ... one day .. I start time machine for my weekly backup .. and this message comes up: "Unable to complete backup. An error occurred while copying files to the backup volume." Now I notice that my external HDD was almost not spinning while time machine was trying to backup ... the status bar of time machine saying how much files need to be copied and the total amount of space needed was super slow .... and stoped at something like maybe 10 mb ... I started time machine again ... same message. I though maybe Mac OSX needed some permission repaires. So I did just that and after that did time machine again ... same problem .... Then I said to myself ... maybe my External HDD has problems ... so I even formated the HDD, then stated Time machine again ... this time it was running smoothly just like before I had the problem ... but the problem came back after 6 gig being copied out of the 25 gig needed to complete the backup process. Now ... I hope I dont need a clean install of my Mac OSX ... or maybe its my external HDD ... maybe my USB having problems ??? Im out of ideas guys ... please help me out.