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I installed Windows 7 using Bootcamp one month ago and it worked fine.

Today, I decided to make another drive in Windows partition.(I didn't know I could not make another drive.) So, I shrank C:\ and made E:\ using disk manager in Windows.(I could not choose D:\ since the driver letter was already assigned).

After I did that, I saw that OSX partition was gone and G and H drives were made. I no longer see boot option to select OSX or Windows when I boot. I can only select Windows. I cannot boot to OSX.

How can I restore OSX? I don't want to lose data in Mac.

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I think you are going to have to start from scratch to actually fix it. However, you can recover your data if you put your Mac in Target Disk Mode. Then you can either use another Mac or a Linux Live CD (which may require you install HFS+ read support) to copy the data you need off the drive. –  nerdwaller Jul 20 '13 at 15:19

1 Answer 1

I'm afraid you made a BAD mistake. Boot Camp configurations rely on a hybrid MBR, in which a standard GPT configuration is extended in a standards-violating manner to include an MBR partition table that replicates some of the GPT partitions. This is useful because, when presented such a disk, OS X sees the GPT partitions but Windows sees the MBR partitions. As Windows will not boot from a GPT disk on a BIOS-based computer (which the Mac appears to be from Windows' perspective), this enables both OS X and Windows to boot from the computer.

The problem is that, if you use a Windows tool to repartition your disk, the MBR data structures are altered but the GPT data structures remain as they originally were. Depending on the details of what was done, this can result in loss of access to the Windows partitions from OS X, damage to some of the OS X partitions that can be difficult to undo, or other problems.

Your best approach is to back up all your data, wipe all the partitioning data from the disk, and then re-install and/or restore your data. Since you say you can boot to Windows, backing up your Windows data shouldn't be difficult. For OS X, you may need to use an OS X emergency disc to do the job. An OS X installation disc might suffice. It's also conceivable that you could use a Linux emergency disc to do the job, but it would be likely to omit some metadata from the backup.

I recommend you complain to Apple about this. It was their ill-conceived notion to use a hybrid MBR that made this type of blunder possible. In the long run, installing Windows in EFI mode (which uses a legal GPT setup) is a better solution. Unfortunately, this is very hard with Windows 7, although some people have succeeded in doing so. It's reportedly easier to install Windows 8 in EFI mode on most Macs, although some people seem to have problems even with that. You might want to consider using Windows 8 in EFI mode when you try again, and therefore bypass hybrid MBRs.

In the meantime, remember rule #1 when using hybrid MBRs:

  1. Never use an MBR-only tool for repartitioning. Use a GPT tool and, if necessary, re-create your hybrid MBR when you're done.
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My Mac is 2009 late model which comes with OS X CD. How can I back up data in OS X with install disc? –  charleyy Jul 20 '13 at 23:07
You can launch the installer and from there launch a Terminal window. Using the Terminal, you can launch most of the programs on your hard disk, although you need to know how to do that. If you're unfamiliar with Terminal, I recommend you locate a tutorial on the Web. (Sorry, I don't have any URLs handy for that.) –  Rod Smith Jul 21 '13 at 19:34

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