I am getting an error message after using time Machine for a few months. It states that it cannot complete the backup, but gives no reason why or how to fix the problem. How do i get this to work again?

Does it say anything apart from the fact that it is unable to complete the update?

As always check your drive and connections, make sure they're all working correctly.

All it says is that there was an error and it was unable to complete the backup. When I look at the external hard drive onto which this goes, I see backups up to through January 13 and then there is one that says the current backup is “in progress”. Thus, the connection must be OK.

The exact message is: "Unable to complete backup. An error occurred while copying files to the backup volume".

If Time Machine gets disrupted for any reason during a backup (ie. hard drive unplugged, power failure) it seems to get stuck. Occasionally it gets stuck for reasons only known to Leopard. Its a known bug on the Apple discussion boards. What has worked for me is the following:
1. ensure hard drive is powered on and connected to computer
2. turn off time machine
3. go to your backup volume, backups.backupd, "your computer name", and then select and trash "In Progress" or "Latest" (it will be the last one in your backup folder listing)
4. turn Time Machine back on
5. either wait for the next backup cycle, or what I do to be sure things are working right is force an immediate backup (control-click on TimeMachine, select "backup now").

You can often find more information on a Time Machine error by checking the system log for Time Machine errors. use the Terminal command:

or use the Console app to access the log and look for Time Machine ("backupd") messages. It might tell you which file gave it trouble.

Time Machine is still quirky.

I recently got the same error message from Time Machine, even though it had been working well for a couple of months.

In my case, the problem was a change in my computer name. I had been working on my home network and my Mac thought there was a duplicate name. It automatically renamed my machine to add "(2)" after the previous name. Turns out that Time Machine doesn't like anything except letters and numbers in the computer name. When I changed my computer name to remove the parentheses, Time Machine started working again.

Seems like if your computer renames itself, it should pick a name that is valid with all the other system-level software, but apparently this one slipped through.

Hope that helps.

Tom

Great Tip. I have had TM display the same error several times in the past ( especially when I used to run .Mac Backup at the same time as TM ) and always just reset my TM backups from scratch ( started with a new backup series ). If it ever happens again I'll have to try this out.