Boot OSX Volume on time capsule.

getting the same thing here, also after doing a TC restore using super duper. hope someone can help with this.

Steve, this appears to be either, an artifact left over from the upgrade to Snow Leopard, or Snow Leopard has made visible something that Leopard kept invisible. Either way, there is only one fix - reformat the TCs' HD. I fiddled with this for two weeks until I finally gave up and did the following:

You have a choice:

a. You can use Airport Utility to Erase/Reformat the TCs HD and begin your Timed machine backups anew.

b. Or, you can do what I did with the 2 TM backup sets from 2 different Macs that I had on my TC. I moved the 2 "Backups.backupd" folders off the TC onto other drives. Reformatted the TCs HD. Created 2 new disk images (sparsebundles) on the TC, and then move the 2 "Backups.backupd" folders back to their respective disk images.

For a more detailed walk-through see the thread post at the link below:

http://discussions.apple.com/thread.jspa?messageID=10709147&#10709147

Mind you, this is a bit involved, and time consuming. But if you MUST preserve your old backups it works. Let us know how it goes for you. Cheers!

I ran into this problem today. For some reason, the disk image has the Boot OSX volume, and you need to get rid of it if you don't want it mounting when Time Machine runs.

If your disk image has an Apple partition map, which it probably does, you're in luck. First open the disk image so the backup volume mounts. In Terminal, run the command df to see which device the image is assigned to. You'll see a line like:

/dev/disk2s3 99868928 53410840 46458088 54% /Volumes/Backup of kali

This tells you the backup volume is partition 3 on device /dev/disk2. You'll need this device name later.

Now, launch Disk Utility, select the backup volume and unmount it. It's important that you unmount the volume rather than eject it so that the image remains associated with the device.

Next, go back to Terminal and run the command sudo pdisk /dev/disk2, modifying the device designator appropriately. In pdisk, the command "p" will list all of the partitions. In my case, the Boot OSX volume was partition 2, so I used the command "d 2" to delete it. Finally, you need to write the modified partition map back to the disk with the command "w", and then you can use the command "q" to quit pdisk.

Finally, go back to Disk Utility and eject the backup volume. Run Time Machine to verify that the Boot OSX volume no longer appears.

(If your disk image has a GUID partition table, this procedure won't work because pdisk only support the Apple partition map, but there is a command called gpt, which apparently allows you to edit GUID partition table. It's left as an exercise to the reader to figure out the proper commands.)

Thumbs Up !

Your instructions worked very well for me.

Thanks a lot.

I moved another backup today, so I took the opportunity to track down when this extra partition gets created. Apparently, SuperDuper is the culprit. When it erases the disk image, it creates a 128-MB Apple_Free partition that resides right after the partition map. Somehow, this gets turned into the Boot OSX partition sometimes.

Hi Conrad. I don't think that SuperDuper! is the issue. I have never used SD but experienced the problem nonetheless. I use CarbonCopyCloner myself, but have never used it on my Time Capsule. So I believe the partition is created by the Mac OS itself, or is created at the factory, and is intended to remain invisible. Installing and updating to Snow Leopard (10.6) has somehow caused this partition to become visible for some users.

The Boot OSX partition isn't on the Time Capsule drive; it's on the disk image Time Machine backs your data up to.

It turns out that Disk Utility is at the root of the problem. In an exchange with SuperDuper!'s developer, I learned that it uses Disk Utility to erase the volume, so I tried erasing the disk image volume directly in Disk Utility and managed to reproduce the problem. CCC apparently erases the volume the same way when doing a block-level copy, which is the only way you can use CCC to copy a Time Machine backup, so it too suffers from this problem. (I just reproduced the problem with CCC here.)

Typically, when this 128-MB partition is created, it's just free space, which doesn't cause a problem, but sometimes, it gets turned into the Boot OSX partition, which is on blessed volumes. I haven't figured out why this happens only on occasion.

Message was edited by: Conrad Hirano

This worked for me but only after ejecting the Boot OSX volume after unmounting the backup partition. Otherwise I would get a "map not writable" message. So I unmounted the backup partition, then ejected the OSX partition via the desktop, and then returned to terminal to run pdisk and delete the OSX partition, etc. This may or may not help others out there with a similar situation.

Thanks for the help!

Conrad, I have never 'touched' my TC with either SuperDuper or CCC. But as you say, it is an issue with Disk Utility. I have only ever used DU on my TC to Verify/Repair the disk images that reside there. Are you saying that these activities create the Boot OS X partition, or 'bless' and existing partition?

That is why my assumption is that this is a normal (invisible) partition that has existed since the purchase of the TC and is only made visible when upgrading to Snow Leopard.

Now another thought I have is, does Time Machine use Disk Utility processes to initially create backup disk images when it is turned ON? If so then I can see these invisible partitions being created at that time.

I haven't found verify/repair to cause the creation of the partition. Erasing the volume with Disk Utility or asr (on the command line) will. It's easy enough to see this behavior: Use Disk Utility to create a sparsebundle with a capacity of 100 GB with a single partition, using APM, not GPT). You can use pdisk to verify that the only partitions are the partition map itself and the volume. Then, back in Disk Utility, select the mounted volume and erase it. (Don't select the image and erase it; that seems to convert it from APM to GPT.) If you look now in pdisk, you'll find there's a new 128-MiB partition in the second slot.

At image creation time, Disk Utility does not include the 128-MiB partition on the image, so when Time Machine first creates the disk image, I wouldn't expect the extra partition to be there.

The creation of the 128-MiB partition isn't that surprising. Apple has designed it so when you partition a large disk, these 128-MiB buffers of free space are created between the volumes. As long as that buffer remains free space, there's no problem, but the buffer sometimes gets turned into the Boot OSX partition and confuses Time Machine. I don't know why that happens.

after following your instructions many times, I keep getting "map not writable". Is this possibly because there are multiple users on my mac? I have even tried to eject the OSX Boot partition once unmounting the backup volume as a latter poster suggested. Nothing seems to work. I still get "map not writable". Any suggestions?

Are you sure you're accessing the correct device? You need to replace "/dev/disk2" with the correct one for the disk image.