Broken Mac OS partition from dual boot — Please help.

[mickiemck]

Hello, I need some help as I accidentally broke the boot partition of my macbook air 11” while trying to erase my ubuntu partition and extend the mac partition. I did this by booting ubuntu from a USB and using the “Disks” program to erase the root partition and the swap area and combine the two together. Then, stupidly, I decided to extend the Mac OS X partition usinng that program and not Disk Utility and as a result when I boot, if I enter target disk mode Mac OS no longer appears and only two partitions labelled “windows” and “windows” appear from Ubuntu. If I choose the first it’ll attempt to boot something but remain stuck on the first line flashing with no text while the second partition will simply freeze and hang.

Can anyone help me? I want to avoid having to erase my disk as there was a whole bunch of important stuff on the Mac Partition. If I’m guessing correctly it isn’t “broken” so to speak, but the bootloader no longer sees it. Would there be any way to correct that?

Thanks for any help in advance.

 

[chscag]

First thing to try is resetting the PRAM. That sometimes will work when Ubuntu GRUB overwrites the EFI boot sector of the Mac. Otherwise, do your best to copy whatever data you can from the Mac side and then erase the drive. Next time before messing with Ubuntu and GRUB, make a clone of your Mac using Carbon Copy Cloner or SuperDuper.