Currently Being ModeratedFeb 17, 2013 1:39 PM (in response to JM1990)
I've not read of anyone else having this problem.
Do you have another partition, such as a Snow Leopard partition. If so, try Disk Utility from there.
If you have disks that came with your computer or a Snow Leopard disc, trying booting from the disc and trying Disk Utility from there.
Currently Being ModeratedFeb 17, 2013 2:14 PM (in response to Eric Root)
Yeah, when I bought the machine it was SL and it's now upgraded through until mountain lion so I will try the disk for SL and see how that goes!
Thanks for the suggestion!
Currently Being ModeratedFeb 17, 2013 5:16 PM (in response to JM1990)
You're welcome. I'd erase the entire disk if possible so when you reinstall, you get a new Recovery Partition, since something isn't right.
Currently Being ModeratedFeb 18, 2013 8:55 AM (in response to Eric Root)
So I tried to reformat with the SL disk in and I was given the error. This operation requires an umounted disk. Now the Disk is mounted but the Mac OS X partition that I want to erase is mounted I think. Is the way around that to unmount the entire disk and then try erase the partiton? I have a Bootcamp partition with a lot of university work and programming programs etc so I would really like to avoid an entire disk reformat.
Currently Being ModeratedFeb 18, 2013 9:43 AM (in response to JM1990)
I've never used Bootcamp but the TroubleShooting section of this link (If You Can't Partition Your Disk) might help.MacBook Pro with Retina display, OS X Mountain Lion (10.8.2), And Mac Mini with OS X (10.8.2)
Currently Being ModeratedFeb 18, 2013 12:18 PM (in response to JM1990)
You might want to consider making a bootable USB/DVD disk in case you have future problems.
You can make a bootable USB/DVD with Mountain Lion with this program: Lion Disk Maker