I have an iMac with which I use a hard-drive-connected Airport Extreme to do backups via Time Machine. This has worked flawlessly for two years. I am not sure if it is a coincidence or not, but shortly after updating to Lion, I started getting dialog boxes saying the backup failed. I could not figure out the problem and ended up just plugging the drive directly into my computer, erasing and re-formatting the partition and starting over. I had Time Machine make the initial back-up whilst the drive was still connected via USB to my desktop and it worked without issue. After that completed, I moved the drive back to the Airport and, upon the first attempt at a follow-up backup, got the message: "The backup disk image “/Volumes/iMac Time Machine/Living Room iMac.sparsebundle” could not be created (error 1)."
I am not sure what to do at this point. Any suggestions?
I hate to be the bearer of bad news but... Time Machine backup over the network is shaky at best. You have a couple of options. First let's make sure you can mount the thing. In the AEBS setup, are you sharing the disk and can you mount the disk from your iMac for regular use? If so you should be able to see the old sparsebundle sitting there. If not, you can spend some time working out why you can't see it. Not being able to see it on the network is actually a better, easier solved situation than being able to see it but can't use it.
If you can see it but are getting the error message, you can browse to the location of your backups and delete (or rename) your old sparsebundle. Yes I said delete (or rename) your old sparsebundle and start over. You can use Disk Utility to check your old sparsebundle for errors but I really think that ship has already sailed. I once spent 45 minutes on the phone with AppleCare trying to work out a messy TM backup over the network only to find out in the end it was better to delete it and start over. So what I'm offering here is the ability to save yourself 45 to 90 minutes IF you are sure you can get through creating a good new backup to use from now on.
I wouldn't start a new backup via usb then move the usb disk to a AEBS and expect to be able to write to that same sparsebundle file. You could rename the old sparsebundle for use via usb and simply let Time Machine create a new one (if there is enough room on the disk).
I have half a dozen Macs successfully backing up over the network to Time Capsule external drive and/or Crashplan. The last time I had a corrupted sparsebundle, I found out about it AFTER my wife's HDD was wiped. I haven't relied on TM as anything more than a convenience ever since.
