Home Forums Mac Software Mac Operating Systems Time machine back up isn't working

Hi there

New to the forum and hoping somebody might be able to help me out.

I've got a iMac OS X Version 10.7.5. Never had any problem backing up to an external hard drive before but suddenly whenever I try I get the message:

"The backup was not performed because an error occurred while copying files to the backup disk. The problem may be temporary. Try again later to back up. If the problem persists, use Disk Utility to repair your backup disk."

I try again later and same think. So I repair the backup disk and it tells me that it's OK. But I still get the same message. Anyone able to offer some advice please?

Many thanks.

Try a third party utility like Disk Warrior or TechTool Pro. See what they tell you about the drive and what repairs they can do.

My main thought is that Time Machine is fine but your hard drive is not. Have another drive available? Try backing up to that. If that works the first drive is the problem. If that does not work, let us know more about the drive and the type of connection (USB, Firewire, etc.).

As a last resort, if you can afford to lose the entire backup, erase the disk using Disk Utility and try again.

Thanks for the reply.

I don't currently have DiskWarrior. Before I buy it, I tried to back up to the WD My Cloud drive. I got the same message. Any further thoughts before I try DiskWarrior?

I'm also running your version of OS X Lion and use Time Machine for backups.

I get the nagging feeling from your description that your OS and/or Time Machine app might be at fault — not Time Machine HD, especially given your last comments.

How about booting into Recovery HD and running Repair Disk — first on your iMac's HD and then, if that doesn't solve the impasse, on your Time Machine HD — from there? If it works, it's a cheap and easy way out.