External drive - volume not mounting

[bmac89]

Hello,

I have an external hard drive with multiple volumes/partitions. One of the volumes has a carbon copy clone of my Mac hard drive and was previously bootable.

I just ran carbon copy cloner to update the backup of my Mac and then proceeded to try booting up the cloned backup. The Apple logo showed and the progress bar slowly progressed but took a very long time. I eventually forced shutdown the Mac by holding the power button and rebooted into the main internal hard drive.

When I tried mounting the external drive only 2 of the 3 volumes mounted and the volume with the backup clone would not mount. I tried opening disk utility but it just said loading disks with spinning wheel for ages. If I eject the external drive disk utility works.

I have tried restarting the computer but it still does not work. When I tried ejecting the other volumes it took a very long time.

Any help would be appreciated - Thanks!

 

[BrianBaughn]

Sounds like you may have caused some corruption on the external partition and possibly on the disk's partitioning itself when you did the shutdown.

You have discovered an issue that can occur with multiple partitions...one bad partition can spoil the whole barrel.

Unless the disk itself is damaged your quickest solution may be to backup what's on the two mounted partitions, wipe and re-partition the drive, and then reload the partitions.

Diskwarrior would be worth a shot if you have it but at $120 and considering this is a CCC partition that you probably just have as an emergency standby the best course is probably the wipe.

 

[Fishrrman]

It's a cloned backup -- you don't have to worry about "losing the data", because you already have access to that data -- it's on your source drive right now.

The problem isn't the data -- it's that the partition isn't booting.
It sounds like something with that particular partition is corrupted.
It may be "fixable", or perhaps not.

Very simple "repair" to try (may work, may not, hurts nothing):
- Power down, all the way off
- Disconnect the drive with the problem partition
- Reboot and get to the finder
- RE-connect the drive with the problem partition... and then....
- ... just "wait a while".
Give it 30 minutes to an hour. The finder will mount the "mountable" partitions, and then try to repair the damaged one. Sometimes, this works. Other times, no.
Again, trying this hurts nothing.

If that doesn't work, I'd recommend this:
1. Back up the stuff on the OTHER TWO partitions of the problem drive.
2. Use Disk Utility to ERASE and then re-partition the ENTIRE drive. I'd also run DU's "repair disk" function on the drive and partitions. If you get a good report, repeat the repair disk function a few times to be sure
3. Set up your partitions so that the CCC clone will be on the "first" partition
4. Restore the other two partitions from your backup
5. Use CCC to create a new cloned backup on the first partition.

Unless there is physical corruption on the drive, the above method is almost 100% guaranteed to work. The disadvantage is that doing it takes some time and effort.

 

[bmac89]

Thanks for the helpful replies.

I managed to wipe the drive and in the process of doing another backup.

The long story:
The bootable partition simply would not mount. Also the other 2 partitions that did mount wouldn’t eject.
Disk Utility was unfortunetly of no use as it would just say loading disks with a spinning progress wheel. Nothing in disk utility would function while this was loading.

I then booted up an old MacBook with snow leopard and the old disk utility was functioning and did find an error but was unable to repair, erase or change any partition as it was unable to unmount the volumes.

I proceeded to copy the data I needed off the external partitions and downloaded a 10 day free trial of Paragon Hard Disk Manager for Mac. Using this I was able to erase the faulty partition knowing that this Could potentially break something... indeed it erased and removed the faulty partition but also messed up the other partition. At this stage I was able to go back to using disk utility and wipe the entire hard drive and it appears to be working ok at present.

 

[Fishrrman]

"...At this stage I was able to go back to using disk utility and wipe the entire hard drive and it appears to be working ok at present."

That's pretty much what I would have done.
Nuke it and start over.