Sparse Disk bundle

[Jamiefort]

I've recently had some issues with Time Machine backing up to a WD External HD via an Airport Extreme. I had to completely reformat the WD hard drive and start the Time Machine back up from scratch. All appears to be working fine BUT when I look at the WD Hard drive via finder, I see the Sparse Disk Image Bundle. It is 110GB in size and last modified matches my last Time Machine back up time. If I double click on the image it says "The following disk images couldn't be opened" and "iMac.sparsebundle image not recognised". Nowhere can I find any 'backups.backupdb" folders as I used to before I had all these problems. I have Yosemite 10.10.2 Any suggestions? Thanks in advance. J

 

[MacInWin]

I think the issue is that when you use TM to backup to a network drive, TM creates a sparcebundle image to save space and network traffic. If the drive is directly mounted to the Mac, it saves as regular files, but on the Network, it shifts to spxrcebundle. So it's not misbehaving, it's acting as designed. To see what's in the spxrcebundle, you have to look at TM. You won't see backups.backupdb because it's not created for the network, the sparcebundle is.

So, did you have the drive previously directly hooked to the iMac and now moved it to the Network?

 

[Slydude]

@Jamiefort I have my Time Machine backup on a drive attached to a Time Capsule. Essentially it is the process you are using.

Occasionally I have trouble with the sparsebundle file and find these two steps correct many problems. One step addresses problems that may be the result of directory structure problems on the hard drive itself. The second addresses problems with the sparsebundle file itself.

1.To address problems with the directory structure of the drive you can't use Disk Utility as long as the physical drive is attached to the Airport Extreme. I've had good luck disconnecting the drive from the network and attaching it directly to the computer. Disk Utility should be able to run now.

2. Sometimes problems occur with the sparsebundle file itself. Try double clicking the sparsebundle file. If the file is not having to many issues it should appear as a sort of virtual hard drive. That drive should appear as a real drive in Disk Utility. Running repair disk on that virtual drive seems to correct some errors with the sparsebundle file.

 

[Jamiefort]

Many thanks Jake for clarifying this for me. I couldn't find info about sparse bundles and Time Machine anywhere.
I initially had the HD hardwired to the iMac but then moved it to the network so that other computers could back up too. I seem to remember it may have asked me if I wanted to keep the same disk. To be honest I can't remember what I said. I did have, however, both a sparse image folder and backupdb as well but thought nothing of it as I didn't know what sparse image was. I then had problem a bit later retrieving a file that I'd lost, which was the start of my problems. I wasn't able to access Time Machine files properly. Initially I tried to fix it over the network but then gave up and wired it to my iMac. Spent hours on the chat with both Apple and WD and after verifying and repairing disks then reformatting the whole lot I backed up successfully with it wired. I then moved it back to the net and that was when I saw the sparse bundles occur. My final act was to hard wire the disk up again, reformat it THEN put it back on the network and THEN do a TM back-up. This has sorted it all out. So Jake, with your great reassuring knowledge of what sparse bundles are I'm in a happy place once again. I've given you the whole 10 shillings in case other readers can benefit from my experiences and adopt the sequence above. Thanks once again. Jamie

 

[Jamiefort]

Hi Sylvester. Thanks for you helpful comments too. Touch wood, it's all working fine, but I'll keep your suggestions in mind for the future. Thanks to all on Mac Forums. Jamie

 

[Slydude]

I've used those tips once or twice. Hope you never need to use them.

Thanks for the rep bump BTW.