Repairing Boot Camp after creating new partition

Thanks - I shall have a read, and see how I go. It is a little scary to attempt more changes having come this far to get a working machine, but I think am getting the hang of it or at least parts of the steps you outlined. Shall keep posted on developments. Thanks...

Firstly let me give a big thanks to Christopher Murphy - his solutioned helped me solve this problem. But it wasn't a complete solution for me because after booting into Windows, I couldn't see the new data partition.

Situation:

1. Reformat HDD and clean install of Mountain Lion

2. Bootcamp and install Windows 7

3. In Mountain Lion, shrink the Mac partition and add a new exFAT partition

The idea was to have a position that I could share between OS X and W7 that wasn't part of either OS.

To fix it, instead of entering "5", I entered "2 4 5" and then answered the questions as:

Type from one to three GPT partition numbers, separated by spaces, to be

added to the hybrid MBR, in sequence: 2 4 5

Place EFI GPT (0xEE) partition first in MBR (good for GRUB)? (Y/N): Y

Creating entry for GPT partition #2 (MBR partition #2)

Enter an MBR hex code (default AF):

Set the bootable flag? (Y/N): N

Creating entry for GPT partition #4 (MBR partition #3)

Enter an MBR hex code (default 07):

Set the bootable flag? (Y/N): N

Creating entry for GPT partition #5 (MBR partition #4)

Enter an MBR hex code (default 07):

Set the bootable flag? (Y/N): Y

Now I windows I can see the Mac OS partition, the Shared partition, and (obviously) the W7 partition.

Here's the complete transcript:

admins-MacBook-Pro:~ admin$ sudo gdisk /dev/disk0

Password:

GPT fdisk (gdisk) version 0.8.5

Partition table scan:

MBR: hybrid

BSD: not present

APM: not present

GPT: present

Found valid GPT with hybrid MBR; using GPT.

Command (? for help): p

Disk /dev/disk0: 1953525168 sectors, 931.5 GiB

Logical sector size: 512 bytes

Disk identifier (GUID): [removed]

Partition table holds up to 128 entries

First usable sector is 34, last usable sector is 1953525134

Partitions will be aligned on 8-sector boundaries

Total free space is 3021 sectors (1.5 MiB)

Number Start (sector) End (sector) Size Code Name

1 40 409639 200.0 MiB EF00 EFI System Partition

2 409640 250409639 119.2 GiB AF00 HDD

3 250409640 251679175 619.9 MiB AB00 Recovery HD

4 251680768 1837617151 756.2 GiB 0700 SHARED

5 1837617152 1953523711 55.3 GiB 0700 BOOTCAMP

Command (? for help): h

b back up GPT data to a file

c change a partition's name

d delete a partition

i show detailed information on a partition

l list known partition types

n add a new partition

o create a new empty GUID partition table (GPT)

p print the partition table

q quit without saving changes

r recovery and transformation options (experts only)

s sort partitions

t change a partition's type code

v verify disk

w write table to disk and exit

x extra functionality (experts only)

? print this menu

Command (? for help): r

Recovery/transformation command (? for help): h

WARNING! Hybrid MBRs are flaky and dangerous! If you decide not to use one,

just hit the Enter key at the below prompt and your MBR partition table will

be untouched.

Type from one to three GPT partition numbers, separated by spaces, to be

added to the hybrid MBR, in sequence: 2 4 5

Place EFI GPT (0xEE) partition first in MBR (good for GRUB)? (Y/N): Y

Creating entry for GPT partition #2 (MBR partition #2)

Enter an MBR hex code (default AF):

Set the bootable flag? (Y/N): N

Creating entry for GPT partition #4 (MBR partition #3)

Enter an MBR hex code (default 07):

Set the bootable flag? (Y/N): N

Creating entry for GPT partition #5 (MBR partition #4)

Enter an MBR hex code (default 07):

Set the bootable flag? (Y/N): Y

Recovery/transformation command (? for help): o

Disk size is 1953525168 sectors (931.5 GiB)

MBR disk identifier: 0x2242231D

MBR partitions:

Number Boot Start Sector End Sector Status Code

1 1 409639 primary 0xEE

2 409640 250409639 primary 0xAF

3 251680768 1837617151 primary 0x07

4 * 1837617152 1953523711 primary 0x07

Recovery/transformation command (? for help): w

Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING

PARTITIONS!!

Do you want to proceed? (Y/N): Y

OK; writing new GUID partition table (GPT) to /dev/disk0.

Warning: The kernel may continue to use old or deleted partitions.

You should reboot or remove the drive.

The operation has completed successfully.

admins-MacBook-Pro:~ admin$

So here's the small problem with adding partitions 2 4 5 to the MBR. You are correct to add partitions 4 5 to the MBR because Windows (booted in BIOS mode) only recognizes MBR on boot disks.

However, by adding partition 2 to the MBR, you leave a small gap in the MBR that tells all MBR aware applications that you have a small 200MB region of free space which is fair game for any app to manipulate. This free space from the MBR's perspective, is actually your Recovery HD partition from the GPT's perspective.

My suggestion is that you redo the hybrid MBR and add partitions 4 5 only. The result is that the GPT, EFI, Mac HD, Recovery HD will all be stuffed in the first MBR entry as 0xEE and will be protected from edits by MBR only aware applications. The Mac OS partition actually does not need to be exposed in the MBR. GPT partitions 4 and 5 will then reside in MBR partition 2 and 3.

Oh and by "redo" I only mean the part in gdisk where you create a new hybrid MBR from the Recovery & Transformation menu.

Hi Christopher - Tried to work through the changes on my computer, but no luck yet. Not sure where I am making a mistake, thought I'd check in here. And that's when I see lemonsoju's solution. Actually, I'd be pretty happy with his set up on mine with possibly a change to NTFS shared space for windows (and use the product you listed earlier for Mac access to NTFS)... Reading it a few times, I think it is workable on my end too given I am having no luck yet. Do you think his approach will work on mine? Thanks...

Ok, tried a couple more of times with the gidsk commands. Windows boots now! And I see another hard drive in Windows, but don't see Mac HDD in My Computer. If I recall, I used to be able to see it.

Have not checked the Mac side yet, hopefully it will be okay too. Fingers crossed...

gmtri - In my post I added partitions 2 4 5 to the hybrid. That allowed me to see the Mac HDD because #2 partition was the Mac HDD. Based of Chris' reply (thanks Chris) I redid it with just 4 5 - so now I see the shared partition (4) but not the Mac HDD.

In short, the partitions you see in Windows depends on which partitions you add to the Hybrid. But as per Chris' comment, you probably dont want to add the Mac HDD.

Thanks lemonsoju for your thoughts. That may well be the case. Although I do recall seeing it before with just mac and windows partition (no shared storage), and only windows being added to the MBR in gdisk. Anycase, that's not a worry if everything else works fine. And as Chris and you say, it is for the better that it is not exposed in windows...

My windows boots now, and I am formatting the new space in windows per Chris' advice. It is taking a while, hopefully will be done... and I need to see if I can get into Mac, and then making sure all works okay. This has been an incredible exercise for someone like me, and a great learning experience, thanks to all of you. Shall keep posted on developments. Cheers...

Here's a stupid question, do the Boot Camp utilities for Windows bring read/write access to HFS+ volumes in Windows? If so, that's the volume format to choose for sharing files between Windows and Mac OS. There's no advantage to buying Tuxera or Paragon NTFS if Apple already provides the functionality to read/write HFS+ from within Windows.

Christopher Murphy wrote:

Here's a stupid question, do the Boot Camp utilities for Windows bring read/write access to HFS+ volumes in Windows? If so, that's the volume format to choose for sharing files between Windows and Mac OS. There's no advantage to buying Tuxera or Paragon NTFS if Apple already provides the functionality to read/write HFS+ from within Windows.

Apples drivers allow read only access to NTFS drives, a 3rd party utility would be needed to allow write access.

Apple's read only is also one of the worst and buggy - MacDrive HFS for Windows, Paragon NTFS (v. 10.0 now) is the best supported current NTFS driver for OS X.

Apple's has trouble mounting, reading files, high overhead, crashes if there is an Apple software RAID present and at various times could BSOD on startup after installing (3.04 and 4.0.0).

OK so the Windows utils Apple supplies, provides read-only JHFS+/X? Not read-write? And they're buggy?

Yet another nail...

I think that VM is the way to do all of this, through its folder sharing.

And for gamers, do they really need to share files between environments? I'd rather have a NAS for Windows/Mac sharing than either buggy implementations, or 3rd party support. I don't understand how a 3rd party can produce better implementations of party 1's file system on party 2's operating system; while neither operating system company can do this correctly. Embarassing.

Success! After all these tries, it looks like things are working as they should. Thanks Scotch for raising this thread, and a big thank you to Christopher for your advice and patience... Hopefully, the computer will continue to perform well going forward... Cheers.

Thank you Christopher! The bootcamp thing worked perfectly for me.

But then something bad happened...

I encrypted my new "Data" partition in OSX and the result was a broken bootcamp again!

So... I ran through your fix again, but this time for some reason bootcamp was listed as partition 6. So I entered number 6 at the appropriate point in your guide, and it worked again. Perfect!

So I now have three partitions - MacHD, Bootcamp, and an encrypted Data partition. And I still have the recovery partition too!

So thanks again Christopher, this has really helped me out. I've only had the Mac two weeks, and it's my first ever Mac. 2012 MacBook Pro 13", i7, 750Gb, 8Gb, Mountain Lion and Windows 7 Ultimate.

Thank you, Thank you, Thank you

:-)