Time Machine error: backup disk image could not be created

Well, it is now March 2009, and this very bug just made me waste 2 hours.

Apple: just ask people to name a name for our new machines, or tell Time Machine to drop us a hint, will ya?

Thanks to all in the thread who provided a solution

You are awesome. I have been fighting this for months. Added a name she worked like a charm. Thanks!!

Thank you, thank you! Made my day or I should say night - been trying to get it to work all day until I found your solution.

Thank you very much! Your post here was far more helpful than anything I found at the Apple Support page!

This bug still exists in Mac OS 10.5.7, May 20, 2009!

I know the answer has been posted, but here it is for the laymen.

I am not a computer technician, but the solution has presented itself so I am passing this along.


If you are having Time Capsule/Time Machine errors that say "the backup disk image could not be created" or other similar to that, please make sure that your computer has a name.

Go to: System Preferences/Sharing-->At the top of the screen there is a text box that says, "Computer Name:" Make sure the computer has been named, or else the Time Capsule/External Hard-drive will not "know" what it's backing up.

Think of it as a person. Would you exchange information with someone if you hadn't stopped to learn their name?

Some of these things may help with the Time Capsule issues
http://www.cfsnap.com/cfsnap.cfm?webtool=Time-Capsule-Errors-Unable-To-Complete- Backup

Thanks so much to you for answering this! I didn't see this mentioned anywhere in my iMac setup process. I am not happy with the process to set up Time Capsule/Time Machine but it's working now. And this forum saved me a trip to the "Genius" bar. (Not that they aren't useful but it is frustrating to go there to get an answer to a question that should be addressed in the normal setup process.)

By the way I have had a Mac since 1986 and never had to name my Mac before. The introduction of wireless networks into the equation has brought in some new details that Apple should help us adapt to.

Thank you for this post. It fixed my problem!

Thank you SO much - so incredibly helpful. It worked and I'm up and running!

Naming the computer made Time Machine work for me too.

Very stupid bug indeed.

I'm getting this problem at the moment. I've read through this thread and tried some of the fixes listed here but no luck yet.

I have a Buffalo NAS external hard drive. It's supposed to be compatible with Time Machine. Spent today trying to set up Time Machine with it, and back up my Macbook. I'm getting the "backup disk image could not be created" error every time. This is the first backup that's been done on the NAS... no joy at all!

I've got no problem accessing the NAS from my laptop, I've transferred a bunch of files from an old PC hard drive onto it and am able to open them. But Time Machine, no luck.

In System Preferences > Shared, I've ensured my computer has a local network name [it's six letters, no punctuation or spaces]. I've created a "backup" folder on the NAS where I want everything to back up to, then set the target host name as my computer's name and entered my computer's MAC address. The NAS tells me it's creating an image file. I mount the "backup" volume on my hard drive. In Time Machine, under Change Disk I selected my NAS, and asked it to back up. It spends a while preparing, but then I get the familiar "backup disk image could not be created" message. One thing I noticed: my boyfriend had a look at this problem too, using his PC laptop to look at the NAS. When we get the NAS to create the image file, he's able to view the changes in the "backup" folder on his PC, but these don't show up on my Macbook when accessing the NAS.

I basically know my way around my computer but at this point I'm just starting to learn to use the command prompt in Terminal, so I'm wary of going at it gung-ho and causing any new problems on my laptop.

I'm keen to try the solution listed here - http://www.readynas.com/?p=253 - will it work for the machine I have, and is it safe for me to try out, given I'm not at all experienced in using Terminal? Have any users here encountered problems with the Buffalo NAS, and found other solutions? Am I missing something very obvious?

synesthesiac wrote:
I'm getting this problem at the moment. I've read through this thread and tried some of the fixes listed here but no luck yet.

I have a Buffalo NAS external hard drive. It's supposed to be compatible with Time Machine.

Hi, and welcome to the forums.

+*Supposed to be+* is probably the critical phrase here.

Time Machine does not back up to network drives, except Time Capsules or a drive running Leopard or Snow Leopard on another Mac on the same local network. It will often back-up to a USB drive connected to an Airport Extreme, but even that is, technically, unsupported, and may require running a special Terminal command to make it work.

Here's the official word: http://support.apple.com/kb/HT1733

You may find some hardware or "hacks" that might make it work, in some cases, to a degree. But use them at your own risk.

First, since this is *unsupported by Apple,* there's nowhere to go when there's trouble.

Second, you're risking a future update preventing it from working, and perhaps rendering your backups useless.

I know Apple won't support other makes of NAS, but this post I found from Pondini worked for me.

**
Hi, and welcome to the forums.

Check your Computer Name at the top of the System Preferences > Sharing panel.

It must not be blank; it should not be more than 25 characters long; and you should avoid punctuation, spaces, and special characters.

After changing it, click the Edit button and make the corresponding change to the Local Hostname.

If that doesn't help, apply the same rules to the name of your Time Capsule and Network, via Airport Utility.
**

It was really as simple as that (after I had done such things as delete the sparsebundle file, created a new one, zeroed-out the new one, nightmare!)

Problem seems to be with OS X's naming of Macs when you first set it up, as it creates a hostname "<yourName>'s Mac Book." When the NAS software (mine anyway) creates the sparsebundle image it replaces the spaces of the hostname with hyphens and strips out the apostrophe, which is never gonna work.