Repairing Boot Camp after creating new partition

Christopher Murphy, I followed your instructions... I managed to boot into windows, but now, the internal storage partition is inaccessible from Windows.

Windows disk management reports it as "GPT protected partition"

I'm running ML 10.8.2

Hallo Chris,

I followed the instructions in this topic and was able to select the Bootcamp partition again in the bootmanager but I am experiencing problems during booting in windows. After running the Windows 8 advanced startup manager and choose the refresh option it brings up the following message.

The drive where Windows is installed is locked. Unlock the drive and try again.

Can you help me with this problem. Is it possible I made a mistake somewhere during the process ?

System setup:

MacBookPro mid 2011 OSX 10.8.2 (12C60)

3 partitions Mac OS, Bootcamp (running windows8) and 10 GB Fat32 partition.

some extra info, I don't know if you need it but this might be helpfull.

sudo gpt -r -vv show disk0 gave the following result:

sudo fdsk /dev/disk0 gave the following:

trying to restore or repair the bootcamp partition by prompt gave the following message:

X:\>chkdsk /f

The type of the file system is NTSF.

Cannot lock current drice.

Windows cannot run disk checking on this volume because it is write protected

X:\>

Thanks Christopher,

I run through all steps again and this time Windows 8 did boot properly so problem is solved.

Many Thanks,

Michael

@Christopher Murphy Hello im experiencing the same exact issue. But i got lost in the steps you provided, is there any way you could please help me in a more simple way of explanation? Thank You

Sorry if you need a simpler explanation it's start over with a reformat, and restore from backup.

I'm running Mac OS X Lion and Windows 7 x64. I installed Windows 7 a few weeks ago, and it's working great. All the Bootcamp drivers are working, and I moved all of my Windows data from my old PC to my Bootcamp installation. However, I also want to install Ubuntu.

I need to create a new partition to install Ubuntu, which I'm going to do by shrinking my Mac OS X partition and creating a partition in Disk Utility. But as I saw in this thread, this breaks the hybrid MBR. I know that I can use gdisk to recreate the hybrid MBR, but first I have a few questions.

First, I want my Windows 7, Mac OS X Lion, and Ubuntu partitions to be in the hybrid MBR. My expected GPT disk layout is as follows:

disk0s1: EFI System Partition

disk0s2: Mac OS X Lion

disk0s3: Lion Recovery Partition

disk0s4: Windows 7

disk0s5: Ubuntu

And my expected MBR layout is this:

1. EFI Protective Partition

2. Windows 7

3. Mac OS X Lion

4. Ubuntu

What command will I need to run in gdisk to accomplish this?

Second, where will GRUB2 be installed? I heard somewhere that GRUB2 installs its code in the EFI Protective Partition. If I install GRUB2 on the boot sector of the Ubuntu partition, will its code be installed in the EFI Protective Partition as well?

Third, in case this goes wrong, is there a way to clone my entire hard drive and restore it if something goes wrong?

EDIT: It seems that GRUB2 actually installs code on the BIOS Boot Partition. And that only happens on BIOS systems. I guess that my memory was a bit off.

I want my Windows 7, Mac OS X Lion, and Ubuntu partitions to be in the hybrid MBR.

This leaves important areas of the disk unprotected.

What command will I need to run in gdisk to accomplish this?

The layout is not ideal. You should have Windows 7 last so that all you add to the MBR is the Windows partition, since that's the only OS that needs MBR.

Second, where will GRUB2 be installed?

In two pieces, first 440 bytes of LBA 0, which will squish the Microsoft BIOS bootloader currently there. The second is core.img and needs to go into its own partition.

I heard somewhere that GRUB2 installs its code in the EFI Protective Partition.

It will not do this because when booting Windows 7 on Apple hardware via Boot Camp, it uses a BIOS-CSM which means GRUB2 core.img needs to go on a BIOS Boot partition.

If I install GRUB2 on the boot sector of the Ubuntu partition, will its code be installed in the EFI Protective Partition as well?

No. And there is no boot sector for Ubuntu's partition using ext[234] because that boot sector is too small (512 bytes) to accept GRUB2's core.img which is usually around 26KB. On MBR disks that normally goes in the MBR gap, but there isn't such a thing on a Mac because the GPT starts where the MBR gap normally is.

I actually need the Mac OS X partition in the MBR so I can get files off of it from Windows. But Ubuntu can be on a GPT partition, right? Also, if GRUB2 can't install on an ext2, ext3, or ext4 partition, will I also need to make a FAT32 partition to install GRUB2 on?

Hello Christopher,

Thank you for the great service you are doing for all of us with this problem.

I hope mine is a simple question. I added a Snow Leopard Boot partition to what had previously been a 2 partition physical drive. Of course, I then lost access to my Bootcamp drive. I really don't need that Snow Leopard Boot to be on this same physical drive: I have all four expansion drive bays on my mid 2010 Mac Pro filled with 2 TB drives, so can partition one of those and delete the Snow Leopard Boot partition off of the drive with Boot Camp. That will leave just two (visible) partitions on the original main physical boot drive--a Mountain Lion Boot partition and the Boot Camp partition. Should this work to restore my accessability to Boot Camp? Should all of my data still be intact?

Thanks in advance! (I won't touch anything until I hear back here.)

Tom Carlson

There is no particularly safe way to do what you want without rearranging the partitions - by safe I mean, ensuring that only OS X and Windows are exposed in the MBR, and everything else is in the 0xEE protective partition of the MBR. However functionally the hybrid MBR you proposed will work.

You do not need to make a FAT32 partition for GRUB, you make a 1MB "BIOS Boot" partition, gdisk type code for this is EF02. It does not need to be formatted, grub-install will automatically find this partition and write core.img to it.

So the BIOS Boot Partition can be outside of the hybrid MBR? Also, what are some of the possible things that could happen if I added my Windows and Mac partition to the hybrid MBR? My hybrid MBR was already set up like this by Bootcamp.

BIOS Boot is unique to GPT, you wouldn't have an entry for it in the MBR as there isn't even a proper type code available for it.

So my expected GPT disk layout is this?

disk0s1: EFI System Partition

disk0s2: Mac OS X Lion

disk0s3: Lion Recovery Partition

disk0s4: Windows 7

disk0s5: BIOS Boot Partition

disk0s6: Ubuntu

disk0s7: Swap

And my expected MBR layout is this?

1. EFI Protective Partition

2. Windows 7

My only other question is what will happen if I do put both the Windows and Mac OS X partitions in the MBR?