[HELP] Lost Mac Partition

You should try to start your MacBook with the original DVD that came with the computer, then reinstall Mac OS X on the Mac partition. Do you have a backup of your Mac data, if not first try to backup your files from the Mac partition first then install Mac OS X.

Can try reinstalling Mac OS X on your Mac partition, you shouldn't lose your data it will just install the OS back on the hard drive, you will be able to keep your Windows Partition, this will work but it depends on how damaged your system partition was, so make sure you have a backup of your data. Then give it a try.

It look like the Mac partition has been deleted you will need to install Mac OS X on that partition and you should be good to go.

Apple's documentation explicitly says not to use 3rd party partition tools to do what you did, for the very reason that it can cause data loss.

The time to do a backup is before you try to resize partitions, especially with an explicitly unsupported tool.

About the only chance you have to fix this is with a command line tool called gdisk. There are linux, Mac OS, and Windows versions. So if you can boot the computer into Windows and install gdisk; or download a linux LiveCD such as Fedora 16 Live CD and while booted off the live cd, install gdisk using yum; or from another hard drive or USB stick that has Mac OS X on it, download and install gdisk.

http://sourceforge.net/projects/gptfdisk/files/gptfdisk/0.8.1/gdisk-binaries/

This command:

gdisk -l /dev/disk0

will display the GPT for disk0 (presumably that is the disk in question, based on screen shots). Depending on what that looks like, you may have a very good chance of getting access to your data, or it's going to be a crap shoot and you'll make the problem worse.

Basically you have to see if the GPT contains valid entries. If it does, all you have to do is go to the recovery menu and create a new hybrid MBR. The way Apple hardware will want this is to add partition 3 into the hybrid MBR.

Yes place EFI GPT in the first MBR.

Accept default hex code.

Yes to set bootable flag.

No to protect more partitions.

Then w to write out the new partition table.

However, if the GPT is also missing your Mac OS X partition, you are very likely screwed. But you could guess at what the start and end sectors were for that partition. Apple's Disk Utilty usually starts EFI at sector 40 and ends on sector 49639. The Mac OS partition will start on 409640 and end just before the start sector for the Boot Camp partition. But that end sector for Mac OS doesn't end right where the Windows partition starts - there's usually a 1024 sector gap. So the Mac OS X end sector will be ~1025 sectors less than the start sector for Boot Camp. It's a guess.

Once that has been added. Then you need to make the hybrid MBR.

Then hope for the best.

Or find yourself someone who does dual boot with linux or freebsd a lot, and have them do this for you.

I've had nearly the same exact issue. I created a bootcamp partition for Windows 8 on my MacBook Pro. I later shrunk my OSX partition size within Mac. I then tried expanding my Windows bootcamp partition into the newly un-alocated space from within Windows using Disk Management. I couldn't figure out how to do it so I called Microsoft tech support. The phone tech controled my computer with remote access, but was also unable to do it. So he then downloaded EaseUS and used it to merge the partitions. After I was off the phone I restarted my Mac to find the Windows & un-alocated partitions were not merged, and even worse, my Mac partition is now listed as un-alocated. I tried restarting in OSX but the Mac partition could not even be seen. Not visible with Disk Repair Utility when my Macbook was hooked up to another computer via target mode either.

My OSX & personal files are all still present and accesible from within Windows but I can't get my MacBook Pro to boot or be visible with target mode so it doesn't seem possible to repair the damage. I've read your instructions above and would first like to confirm this is also the same solution for my issue before any more damage is done. Secondly, before I begin I'd really be more comfortable to have somone that knows what they're doing fix this. What is this issue called exactly? Thank you.

Please post the results from the following read-only commands, formatting them with Andale Mono font to make it easier to read.

sudo gpt -r -vv show disk0

sudo fdisk /dev/disk0

'sudo' is not recognized as an internal or external command, operable program or batch file.

Oh, right, you're only able to boot Windows. Those were OS X commands. Grab a copy of gdisk for Windows here. I can't tell you how to launch it on Windows, as I've never used it on Windows. Basically you need to point it to a drive, and you'll find it in interactive mode. r <enter> to get to the recovery menu, and o <enter> to spit out the MBR contents, and p <enter> to spit out the GPT, and q <enter> to quit without making any changes (which those commands don't do anyway). Then copy-paste those results. Again, use andale mono or the results are difficult to read.