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Unable to boot up in bootcamp after installing Mountain Lion

55296 Views 130 Replies Latest reply: Jun 2, 2013 3:21 PM by Christopher Murphy RSS
  • Christopher Murphy Level 2 Level 2 (470 points)

    The GPT and MBR agree with each other exactly. I see no problem, although I'm unsure how the GPT was updated to reflect the MBR, since the Windows installer would have only added entries to the MBR, not the GPT. In any case, it looks fine right now.

     

    everything has been working fine till I used Disk Utility to reduce the size of the Mac partition

     

    I don't understand what this means: 1.) Why were you reducing the size of the Mac partition? 2.) How are things no longer working?

     

    Do you think that this configuration is ok to try resizing the partitions again? Any advice or remarks on doing this?

     

    Yes, you need to leave things alone. MBR only supports four partitions maximum, and presently you have four partitions. By resizing one of them, you imply you're adding a fifth partition for some purpose. While that fifth partition can exist in the GPT just fine, there's no corresponding place for it in the MBR, in the way Apple's tools create hybrid MBRs. When others have tried adding a fifth partition, the hybrid MBR is blown away in favor of a conventional single entry protective MBR, which in turn renders Windows unbootable.

  • g5cal Calculating status...

    Christopher Murphy wrote:

    >How many times has this disk (any partition or partitions) been formatted NTFS?

     

    Just like jamocag, I resized my Boot Camp partition a while before installing OS X 10.8.

    I suppose that it screwed up the partition schemes (not beeing syncronized).

     

    I would really like to try and get my partition scheme back to where it was, just to be able to mount the partition and rescue some of the files.

     

    user$ sudo hexdump -C /dev/disk0s4 | grep 'eb 52 90 4e 54 46 53 20'

    3e64c000  eb 52 90 4e 54 46 53 20  20 20 20 00 02 08 00 00  |.R.NTFS    .....|

    459f2c000  eb 52 90 4e 54 46 53 20  20 20 20 00 02 08 00 00  |.R.NTFS    .....|

    524e70000  eb 52 90 4e 54 46 53 20  20 20 20 00 02 08 00 00  |.R.NTFS    .....|

    56a0ec000  eb 52 90 4e 54 46 53 20  20 20 20 00 02 08 00 00  |.R.NTFS    .....|

    1174146590  4f 00 00 82 3e 00 55 aa  eb 52 90 4e 54 46 53 20  |O...>.U..R.NTFS |

    12a3798000  eb 52 90 4e 54 46 53 20  20 20 20 00 02 08 00 00  |.R.NTFS    .....|

    12a39ffe00  eb 52 90 4e 54 46 53 20  20 20 20 00 02 08 00 00  |.R.NTFS    .....|

     

    Doesn't the three blocks seem to correspond like this?

     

    3e64c000  eb 52 90 4e 54 46 53 20  20 20 20 00 02 08 00 00

    Start> 459f2c000  eb 52 90 4e 54 46 53 20  20 20 20 00 02 08 00 00

    Start> 524e70000  eb 52 90 4e 54 46 53 20  20 20 20 00 02 08 00 00

    Start> 56a0ec000  eb 52 90 4e 54 46 53 20  20 20 20 00 02 08 00 00

    <End 1174146590  4f 00 00 82 3e 00 55 aa  eb 52 90 4e 54 46 53 20

    <End 12a3798000  eb 52 90 4e 54 46 53 20  20 20 20 00 02 08 00 00

    <End 12a39ffe00  eb 52 90 4e 54 46 53 20  20 20 20 00 02 08 00 00

     

    They seem to have the same "distance" between eachother?

     

    Maybe I should try with the last "Start block" and the last "End block" ?

  • jomocag Calculating status...

    I'm unsure how the GPT was updated to reflect the MBR, since the Windows installer would have only added entries to the MBR, not the GPT.

     

    I'll try to clarify this. I did my bootcamp installation in Feb-2010. During the w7 installation, I deleted the partition created by the bootcamp assistant and let the w7 installation to create its partition. As you suggested, this decision probably caused a discrepancy MBR and GPT. Around 5 days ago I used Disk Utility to decrease the size of the Mac partition, as it has 290GB available and I mostly use W7. I rebooted the machine to enlarge the w7 partition using a windows program but it didn't boot anymore.

     

    In any case, it looks fine right now.

     

    Thanks to your posts helping other people.

     

    I don't understand what this means: 1.) Why were you reducing the size of the Mac partition? 2.) How are things no longer working?

     

    Sorry, I should have written "everything had been working fine..."

     

    Yes, you need to leave things alone. MBR only supports four partitions maximum, and presently you have four partitions. By resizing one of them, you imply you're adding a fifth partition for some purpose. While that fifth partition can exist in the GPT just fine, there's no corresponding place for it in the MBR, in the way Apple's tools create hybrid MBRs. When others have tried adding a fifth partition, the hybrid MBR is blown away in favor of a conventional single entry protective MBR, which in turn renders Windows unbootable.

     

    Understood, but there should be some way of redistributing the available space among the existing partitions without creating a mess in the partitions table.

  • Christopher Murphy Level 2 Level 2 (470 points)

    Understood, but there should be some way of redistributing the available space among the existing partitions without creating a mess in the partitions table.

     

    Apple doesn't provide tools that can do this. There are 3rd party tools that can, but I don't know all of the differences between their features and capabilities. The three off hand I know about are Winclone, iPartition, and CampTune. I suggest some searches for comparisons between these tools.

  • Christopher Murphy Level 2 Level 2 (470 points)

    This is beyond my knowledge area. When I create NTFS partitions from scratch of various sizes, they contain only two such R.NTFS instances marking the first and last sectors of the volume. I don't know what it means where there are more. I don't know if these are prior NTFS volumes and this data simply isn't removed between reformats? Or if it indicates something else. Maybe these additional references are created as the volume is filled to a certain point.

     

    If you boot from a Windows install disk, and manually run chkdsk, followed by chkdsk /f I'd be curious if that comes up clean or not. And if it does, or makes minor repairs, then that should at least mean you can mount the volume in Mac OS X, and get your data off (assuming you don't have a recent backup, this is your first priority not getting it to boot again).

     

    This doc has more info on this, but you have to click on "click here to show more" to get the commands to run. I would do it in order of:

    /FixMbr

    /FixBoot

    /RebuildBcd

  • Quebsez Calculating status...

    I am having the same problem as you, but I have no idea how to actualy boot from the Windows 7 disk. How did you do it? Any details you can provide would be greatly appreciated.

  • coxorange Level 1 Level 1 (40 points)

    Hi

     

    Sorry it's urgent. I need Winclone immediately. Does anyone know, if I would buy it now, would it be possible to download and use it instantly? Sorry I found no information about that on their website but I guess some of you already bought it.

     

    Many thanks!

  • Csound1 Level 7 Level 7 (32,380 points)

    coxorange wrote:

     

    Hi

     

    Sorry it's urgent. I need Winclone immediately. Does anyone know, if I would buy it now, would it be possible to download and use it instantly? Sorry I found no information about that on their website but I guess some of you already bought it.

     

    Many thanks!

    You can use it immediately after you buy, download and install it.

  • coxorange Level 1 Level 1 (40 points)

    Thanks!

  • Quebsez Level 1 Level 1 (0 points)

    I am having a similar problem with my partition, but I dont know how to boot from the windows disk. Could you please explain how?

  • TDLI Level 1 Level 1 (0 points)

    @ CM

     

    I downloaded gdisk and have been making "changes" in terminal.  I made minor progress, but still unable to get into Windows 7 to access my files.  Here is where I am:

     

    The Good

     

    When I press the "Option" key during boot up I see all 3 drives, the mac drive, the windows drives and the recovery drive.  (Before I saw your post I only had 2 drives, mac drive and recovery drive.)

     

    The Bad

     

    When I try to boot into my windows 7, I get the message "Operting system missing"

    When I use disk utility, the name of the windows partition still shows up as "disk04s"

     

    I am the same as everyone else.  Upgraded to ML and now cannot access Windows 7.

     

    Can you help me?  Thanks.

  • Christopher Murphy Level 2 Level 2 (470 points)

    I don't know exactly what you did so I have no idea how to help you. But it sounds like you resized the Boot Camp volume from within Windows, it was working fine until you upgraded to Mountain Lion and now you can't boot?

     

    Basically what it sounds like is happening is that the start position of the NTFS volume is altered when you resize, and that information is put in the MBR. Upon discovering the mismatch between MBR and GPT, the installer is resyncing from GPT to MBR, which causes critical information (the start of the Boot Camp volume) to be lost from the MBR. This is pure speculation on my part, because I haven't actually reproduced this yet (nor tried it), but it does seem to square with the volume of facts thus far.

     

    Once that information is lost (the start sector for Boot Camp) from the MBR, it's like a needle in a haystack to find it.

     

    dd if=/dev/disk0s4 of=~/disk0s4_2s.bin count=2

    hexdump -C ~/disk0s4_2s.bin

     

    So the above creates a file called "disk0s4_2s.bin" that contains the raw binary data found in the first 2 sectors of disk0's 4th partition, saved to your home folder; and then displays the hex values for that file on-screen. You're basically looking for something like this:

    http://bootmaster.filerecovery.biz/appnote3.html

     

    In particular the first row which identifies the start of an NTFS volume. If you don't have that first line identifying it as NTFS then the current GPT has the wrong start sector for the Boot Camp volume and if you really want the data from that volume it's going to take a while to find it.

  • TDLI Level 1 Level 1 (0 points)

    Hi CM, I actually did not resize anything myself in Boot Camp.  All I did was upgraded from Leopard to ML then I could not get access to my Boot Camp Windows 7 drive anymore.

     

    I followed your instructions and downloaded gdisk and was able to make my Windows 7 drive show up when I press on the "Option" key, but I am getting the "Operting system missing" error message.

     

    Here is the return from the above two commands:

     

    sudo dd if=/dev/disk0s4 of=~/disk0s4_2s.bin count=2

    Password:

    2+0 records in

    2+0 records out

    1024 bytes transferred in 0.000348 secs (2943775 bytes/sec)

     

    hexdump -C ~/disk0s4_2s.bin

    00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

    *

    00000400

     

    I have very little knowledge with computer programming but I am pretty good with following instructions so anythinig you can do to help would be great, thanks.

  • TDLI Level 1 Level 1 (0 points)

    And here are the returns from some of the commands you requested in earlier posts:

     

    sudo gpt -r -vv show disk0

    Password:

    gpt show: disk0: mediasize=121332826112; sectorsize=512; blocks=236978176

    gpt show: disk0: Suspicious MBR at sector 0

    gpt show: disk0: Pri GPT at sector 1

    gpt show: disk0: Sec GPT at sector 236978175

          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  116435120 2  GPT part - 48465300-0000-11AA-AA11-00306543ECAC

      116844760    1269544 3  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

      118114304  118861824 4  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

      236976128       2015        

      236978143         32         Sec GPT table

      236978175          1         Sec GPT header

     

     

    sudo fdisk /dev/disk0

    Disk: /dev/disk0       geometry: 14751/255/63 [236978176 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 - 116435120] HFS+       

    3: AB 1023 254  63 - 1023 254 63 [ 116844760 -    1269544] Darwin Boot

    *4: 07 1023 254  63 - 1023 254  63 [ 118114304 -  118861824] HPFS/QNX/AUX

     

    diskutil list /dev/disk0

    /dev/disk0

       #:                       TYPE NAME                    SIZE       IDENTIFIER

       0:      GUID_partition_scheme                        *121.3 GB   disk0

       1:                        EFI                         209.7 MB   disk0s1

       2:                  Apple_HFS Mac HD                  59.6 GB    disk0s2

       3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3

       4:       Microsoft Basic Data                         60.9 GB    disk0s4

  • Christopher Murphy Level 2 Level 2 (470 points)

    There's no mismatch between the GPT and hybrid MBR. And there's nothing in the first two sectors of disk0s4. If you've never resized the Windows volume, I don't have an explanation for why it's missing and therefore no way to tell you how to get it back. The usual suggestion to run Windows Startup Repair from the Windows install disk applies.

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