"Unable to complete backup. An error occurred while copying files..."

Same issue. I am trying to backup to an internal drive with 150GB available (nothing else on the drive). This WAS my boot drive until I moved everything to what was my cloned backup in TIger.

Leopard installed first time on the clone, but refused to install on the boot drive. I formatted the old boot drive with Disk Utility provided on the Leopard disk,an d tried it with partitions large enough for a full backup as well as with no partitions.

So far, Time Machine has failed to backup anything. It stops and the G5 goes into a kernel panic.

I have been told that Leopard is "not as compatible" with PPCs as it is with Intel machines and I do know that this is the last Mac OS that will be useable on non-Intel machines. Not sure that is relevant but it might be worth noting.

Me too, same error with a MacBook

I have the same problem - seemed to backup to my western digital partitioned 500gig ok the first time - but now keep getting same 'error' on subsequent backups.

This problem seemed to resolve itself during the night - TM now working perfectly. Maybe it just needed more time to sort itself out.

Yep. Same here. Formatted the drive twice already and backup attempted 3 times to no avail...

I've been having the same problem for the last 2 days. Each time, the (full) backup proceeds to ~60GB, and then hangs and fails near the end of the backup with the "Unable to complete backup. An error occurred while copying files to the backup volume" message. I then stop Time Machine, delete the backups.backupsdb folder from the external hard drive, and start over.

By start over, I mean I delete all of the backup files from the external drive, and then hit "Backup Now" in the Time Machine right-click menu. It starts a full backup again from scratch, I think; each time it backs up a full 63GB before failing.

Is there a particular drive formatting needed?

You might also try excluding large folders and any Entourage folders (I think in user/application support). This worked for me. I'll try adding my large folders in when I get a bigger external (1TB) and let you know if it worked.

I am having the same trouble. MacBook Pro, Intel 2.0

I have formatted the drive a few different ways, but the same result, with a very unhelpful error message.

I have a new iMac at home and it worked like a charm. This is a business machine, so frankly I need the backup more urgently, and am now running with scissors until this works.

I just got the same error message: "Unable to complete backup...". But I've been using Time Machine for a few days now, backing my Mac Mini up to an external USB drive. When I checked a couple of days ago, that drive had TM data on it - now it doesn't ("sudo du -s" from /Volumes/Backup1 results in "40"). So not only is TM not working, it destroyed an existing backup disc!

I reformatted my backup hard drive then started over again when this happened to my setup. No problems since then.

Regards,