Time Machine, Mac OS X Leopard’s built-in backup software is great when it works, and it usually does just fine. However, it has a bad habit of occasionally alerting the user that it didn’t work, with something like this:

While annoying, 99% of the time its nothing to worry about. To check, just go to your menu bar, click on the Time Machine icon…

If it shows that the latest backup was within the last hour, then you know that every is working fine. Why does this happen? Sometimes there’s a small file or two that is busy when Time Machine runs, and it throws up this error. But the next time Time Machine runs, these files can be copied, and and the backup goes ahead. The alert box, however, still hangs around, cuasing confusion. I think this is a Time Machine interface bug that I hope will be fixed or changed in future version of OS X. For now, now that you know how, you can safely ignore it.