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Scotch_Brawth Author

Level 3

827 points

Repairing Boot Camp after creating new partition

I'm running OS X 10.8 and Windows 7 x64 Pro.

After properly setting up Boot Camp to dual-boot Windows on my Mac mini, I decided to test whether or not it was true that creating another partition (a data partition for OS X) would interfere with Boot Camp. Wikipedia claims it does interfere but without citing a source, whilst the Boot Camp documentation itself only specifies that the disk must be a single partition _prior_ to setup - there's no mention of whether the disk must be _kept_ that way afterwards.

I opened Disk Utility, reduced the size of my OS X parition from 420GB to 80GB, and created a new partition in the unallocated space. Here's how it looks now:

When I attempted to proceed with the process, I did receive a warning that doing this (and I quote), "may" cause problems with Boot Camp. Seeing as it was inconclusive, I thought I'd give it a shot - nothing ventured…

Of course, it borked Boot Camp, otherwise I wouldn't be posting here. Whilst OS X boots just fine, the Boot Camp partition now no longer shows up in the Startup Manager, though it does in the Startup Disk prefPane. If I do attempt to boot into Boot Camp, I receive the following message on a black screen:

No bootable device --- insert boot disk and press any key

The advice given to someone who had this same problem was, "fix your damaged Boot Camp volume." But I'm at a loss as to how to do that.

So, anyone know how to proceed now so that I can keep my partitions as is, whilst fully restoring normal Boot Camp functionality?

Mac mini (Mid 2011), Mac OS X (10.7.4)

Posted on Jul 26, 2012 11:28 PM

1,534 replies

Dec 13, 2012 4:59 PM in response to Christopher Murphy

Thank you Christopher

Although I gained another issue, I spent the day on windows 7 and decided to boot into mac os

for some god un known reason my second raid slice was "missing" and would not boot....

was so disapointed so i was forced to reinstall, the second raid device would not show in mac os installer untill i deleted the raid disk entirely then i had to reinstall a time machine back up.

at the same time i deleted the windows 7 first to hope that my other raid slice would appear.

so back to square one i dont know what the issue was. sad face 😟

Unsure if i want to attempt todo this all over again, in case i get the same problem

I cant officially use bootcamp to partition my drive because... bootcamp assistant complains that i dont have a dvd drive and cant detect my installer, there for refuse to partition my drive correctly, so im stuck with disk utility.... any suggestions?

Dec 13, 2012 6:02 PM in response to Coffeecoco

VM's are the way to do this. I find Boot Camp totally irritating and risky. If we get UEFI/GPT supported Windows 8 installs, then I might change my mind. But right now you have to tread an extremly narrow path, some of which Apple does not document well, and if you go off the path, abruptly you can find yourself in the world of data loss, and rebuilding a computer for a day or two.

Dec 13, 2012 6:09 PM in response to Coffeecoco

Oh and Disk Utility is treacherous. I trust it with very little these days, in the way of partitioning. I never use it for repartitioning or resizing.

Dec 14, 2012 7:47 AM in response to Christopher Murphy

BTW i still can't find a decision how to fix Windows MBR because Paralles doesn't allow to modify it and VM Vare fusion fixed it BUT only for itself. So now i'm running under VM Vare.
The main problem that i can't but CD-Rom back to macbook because i Windows is on the secondary disk that is placed instead of CDrom. And there is no possibility to start Windows from USB. Stupid situation... The only hope is to try USB external CD-Rom. I hope it will work but have doubds because of USB connection.

Dec 14, 2012 9:02 AM in response to Alex Senkevich

It's possible this could be fixed from a linux LiveCD that supports EFI booting, which is needed to boot non-recent Apple hardware from USB. From there you can write a replacement boot loader to LBA 0. The one I'm thinking of is Fedora 17. The Live CD can be written directly to a USB stick using dd on OS X. Once booted, the CD should contain a suitable mbr replacement in the syslinux folder (it is on the Fedora 18 final test candidate I'm testing now); all this bootloader does is tell the CPU to jump to the first sector of whatever partition is flagged as bootable in the MBR. That's it. And that's all you need it to do. Once it's jumped from LBA 0 to your Windows partition the computer should boot just like it does your VM. In theory. If not, the nice thing about a LiveCD is that you have full internet access, and can download other files including a real microsoft LBA 0 boot loader for that first sector. But seriously, it's a tiny bit of code, only 440 bytes. So if it works, it's completely unused after that and can't cause further problem down the line. It's purely jump code.

Dec 21, 2012 6:06 PM in response to Christopher Murphy

Hello Christopher, i tried to make my windows partition live but without any results. Different VMs even usb CD-ROM.
So i moved Windows partition to Mac OS hard disk to be able to connect Internal CD-ROM and recreate Windows MBR. So i need repeat procedure of hybrid MBR. Please help me to understand what is wrong now.

I would like to understand for not to bother you in future.

Thank you.

===================================================

sh-3.2# diskutil list

/dev/disk0

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *256.1 GB disk0

1: EFI 209.7 MB disk0s1

2: Apple_HFS Users 255.7 GB disk0s2

/dev/disk1

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *240.1 GB disk1

1: EFI 209.7 MB disk1s1

2: Apple_HFS Mac OS 179.0 GB disk1s2

3: Apple_Boot Recovery HD 650.0 MB disk1s3

4: Microsoft Basic Data Windows 7 60.1 GB disk1s4

===================================================

sh-3.2# gpt -r -vv show disk0

gpt show: disk0: mediasize=256060514304; sectorsize=512; blocks=500118192

gpt show: disk0: PMBR at sector 0

gpt show: disk0: Pri GPT at sector 1

gpt show: disk0: Sec GPT at sector 500118191

start size index contents

0 1 PMBR

1 1 Pri GPT header

2 32 Pri GPT table

34 6

40 409600 1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B

409640 499446368 2 GPT part - 48465300-0000-11AA-AA11-00306543ECAC

499856008 262151

500118159 32 Sec GPT table

500118191 1 Sec GPT header

===================================================

sh-3.2# fdisk /dev/disk0

Disk: /dev/disk0 geometry: 31130/255/63 [500118192 sectors]

Signature: 0xAA55

Starting Ending

#: id cyl hd sec - cyl hd sec [ start - size]

------------------------------------------------------------------------

1: EE 1023 254 63 - 1023 254 63 [ 1 - 500118191] <Unknown ID>

2: 00 0 0 0 - 0 0 0 [ 0 - 0] unused

3: 00 0 0 0 - 0 0 0 [ 0 - 0] unused

4: 00 0 0 0 - 0 0 0 [ 0 - 0] unused

===================================================

sh-3.2# gpt -r -vv show disk1

gpt show: disk1: mediasize=240057409536; sectorsize=512; blocks=468862128

gpt show: disk1: Suspicious MBR at sector 0

gpt show: disk1: Pri GPT at sector 1

gpt show: disk1: Sec GPT at sector 468862127

start size index contents

0 1 MBR

1 1 Pri GPT header

2 32 Pri GPT table

34 6

40 409600 1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B

409640 349609376 2 GPT part - 48465300-0000-11AA-AA11-00306543ECAC

350019016 1269536 3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

351288552 792

351289344 117448704 4 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

468738048 124047

468862095 32 Sec GPT table

468862127 1 Sec GPT header

===================================================

sh-3.2# fdisk /dev/disk1

Disk: /dev/disk1 geometry: 29185/255/63 [468862128 sectors]

Signature: 0xAA55

Starting Ending

#: id cyl hd sec - cyl hd sec [ start - size]

------------------------------------------------------------------------

1: EE 0 0 2 - 25 127 14 [ 1 - 409639] <Unknown ID>

2: AF 25 127 15 - 1023 254 63 [ 409640 - 349609376] HFS+

*3: AB 1023 254 63 - 1023 254 63 [ 350019016 - 1269536] Darwin Boot

4: 00 0 0 0 - 0 0 0 [ 0 - 0] unused

===================================================

sh-3.2# dd if=/dev/disk0 count=1 2>/dev/null | hexdump -C

00000000 fa 31 c0 8e d8 8e c0 8e d0 bc 00 7c fb fc 89 e6 |.1.........|....|

00000010 bf 00 06 b9 00 01 f3 a5 ea 1d 06 00 00 88 16 00 |................|

00000020 08 b4 08 cd 13 31 c0 88 f0 40 a3 f0 06 80 e1 3f |.....1...@.....?|

00000030 88 0e f2 06 be be 07 31 c0 b9 04 00 f6 04 80 74 |.......1.......t|

00000040 03 40 89 f7 83 c6 10 e2 f3 83 f8 01 75 73 8a 16 |.@..........us..|

00000050 00 08 b8 00 41 bb aa 55 31 c9 30 f6 f9 cd 13 72 |....A..U1.0....r|

00000060 23 81 fb 55 aa 75 1d f6 c1 01 74 18 57 be e0 06 |#..U.u....t.W...|

00000070 8b 5d 08 89 5c 08 8b 5d 0a 89 5c 0a 8a 16 00 08 |.]..\..]..\.....|

00000080 b4 42 eb 2a 57 8b 45 08 8b 55 0a f7 36 f2 06 42 |.B.*W.E..U..6..B|

00000090 89 d1 31 d2 f7 36 f0 06 88 c5 d1 e8 d1 e8 24 c0 |..1..6........$.|

000000a0 08 c1 88 d6 8a 16 00 08 bb 00 7c b8 01 02 cd 13 |..........|.....|

000000b0 72 16 5e 81 3e fe 7d 55 aa 75 08 fa ea 00 7c 00 |r.^.>.}U.u....|.|

000000c0 00 77 05 be f4 06 eb 03 be 0f 07 ac 20 c0 74 0c |.w.......... .t.|

000000d0 b4 0e 8a 3e 62 04 b3 07 cd 10 eb ef eb fe 00 00 |...>b...........|

000000e0 10 00 01 00 00 7c 00 00 00 00 00 00 00 00 00 00 |.....|..........|

000000f0 00 00 00 00 4d 69 73 73 69 6e 67 20 6f 70 65 72 |....Missing oper|

00000100 61 74 69 6e 67 20 73 79 73 74 65 6d 0d 0a 00 4f |ating system...O|

00000110 70 65 72 61 74 69 6e 67 20 73 79 73 74 65 6d 20 |perating system |

00000120 6c 6f 61 64 69 6e 67 20 65 72 72 6f 72 0d 0a 00 |loading error...|

00000130 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|

000001b0 00 00 00 00 00 00 00 00 11 a9 fe 7d 00 00 00 fe |...........}....|

000001c0 ff ff ee fe ff ff 01 00 00 00 af 32 cf 1d 00 00 |...........2....|

000001d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|

000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.|

00000200

===================================================

sh-3.2# dd if=/dev/disk1 count=1 2>/dev/null | hexdump -C