5 Replies Latest reply: Oct 22, 2013 7:52 PM by Christopher Murphy
Random_Tangent Level 1 Level 1 (0 points)

Had a sound bug in Windows, so I figured a soft reboot wouldn't hurt. Guess I was wrong. Instead of zipping right back into Windows, the machine (a Mac Pro 3,1) hangs on white and can't boot into Windows. I've had a similar problem in the past, but was never able to nail down the cause. (I think something's looking at my MBR and deciding it's free space instead of protected, but that's a guess).

 

Here's the output of a "sudo gpt -r -vv show disk0"


gpt show: disk0: mediasize=250059350016; sectorsize=512; blocks=488397168

gpt show: disk0: Suspicious MBR at sector 0

gpt show: disk0: Pri GPT at sector 1

gpt show: disk0: Sec GPT at sector 488397167

      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   96092960      2  GPT part - 48465300-0000-11AA-AA11-00306543ECAC

   96502600    1269536      3  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

   97772136       1432        

   97773568  390623232      4  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

  488396800        335        

  488397135         32         Sec GPT table

  488397167          1         Sec GPT header

 

Someone cleverer than me out there on a Sunday evening?


Mac Pro, OS X Mountain Lion (10.8.4)
  • 1. Re: Windows 7 Bootcamp MBR has gone AWOL. Any ideas on getting it back?
    Random_Tangent Level 1 Level 1 (0 points)

    may as well output FDISK while I'm at it.

     

             Starting       Ending

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

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

    1: EE 1023 254  63 - 1023 254  63 [         1 -     409639] <Unknown ID>

    2: AF 1023 254  63 - 1023 254  63 [    409640 -   96092960] HFS+       

    3: AB 1023 254  63 - 1023 254  63 [  96502600 -    1269536] Darwin Boot

    *4: 07 1023 254  63 - 1023 254  63 [  97773568 -  390623232] HPFS/QNX/AUX

  • 2. Re: Windows 7 Bootcamp MBR has gone AWOL. Any ideas on getting it back?
    Christopher Murphy Level 3 Level 3 (525 points)

    The two partition tables appear to be synced, so the problem lies elsewhere. Consider booting from the install DVD and running Windows Startup Repair. If that doesn't find anything wrong or fix the problem, then I'd move on to this support document about the bootrec.exe tool. You can do this in any order, or all three of them at the same time, but the support document is kinda densely written IMO. You have to click the big

    + Bootrec.exe options

    link to reveal the actual options. What's non-obvious is you can either type bootrec.exe and then separately type:

     

    /FixMbr

    /FixBoot

    /RebuildBcd

     

    Or you can use the vernacaular of 'bootrec <option>' e.g.

     

    bootrec /FixMbr

     

    Also non-obvious is the last ditch effort which is if the above three don't work, do this exactly as documented:


    bcdedit /export C:\BCD_Backup

    c:

    cd boot

    attrib bcd -s -h -r

    ren c:\boot\bcd bcd.old

    bootrec /RebuildBcd


  • 3. Re: Windows 7 Bootcamp MBR has gone AWOL. Any ideas on getting it back?
    Random_Tangent Level 1 Level 1 (0 points)

    Well, never got a chance to try this out as Windows randomly decided to not hang at boot. So, I have no idea now. Time to backup everything and wipe the drive.

     

    You're a prince, Christopher Murphy. A true prince.     

  • 4. Re: Windows 7 Bootcamp MBR has gone AWOL. Any ideas on getting it back?
    talitridae Level 1 Level 1 (0 points)

    Hi-

     

    I too had a BootCamped install crap out on me when I accidentally shut my computer with windows running. When I pulled it out of my bag, the machine was HOT and would only launch in windows. I reinstalled OSX and see my bootcamp partition but the computer doesn't see it when I option+start.

     

    I have read through pages and pages of the fixes but am not totally clear on how to get it back. I am wondering if someone can help.

     

    Here's the info that seems to be needed. As far as I can see, it should be healthy but I am far from knowledgable.

     

    Thanks for looking!

     

     

    Last login: Thu Aug 22 14:21:17 on ttys000

    myMBP:~ x$

    myMBP:~ x$

    myMBP:~ x$ sudo gpt -r -vv show disk0

    Password:

    gpt show: disk0: mediasize=750156374016; sectorsize=512; blocks=1465149168

    gpt show: disk0: PMBR at sector 0

    gpt show: disk0: Pri GPT at sector 1

    gpt show: disk0: Sec GPT at sector 1465149167

           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        2008       

          411648  1070309376      2  GPT part - 48465300-0000-11AA-AA11-00306543ECAC

      1070721024        1128       

      1070722152     1269536      3  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

      1071991688        1144       

      1071992832   393148416      4  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

      1465141248        7887       

      1465149135          32         Sec GPT table

      1465149167           1         Sec GPT header

     

     

     

     

    myMBP:~ x$ sudo fdisk /dev/disk0

    Disk: /dev/disk0     geometry: 91201/255/63 [1465149168 sectors]

    Signature: 0xAA55

             Starting       Ending

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

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

    1: EE    0   0   1 - 1023 254  63 [         1 - 1465149167] <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    

     

     

     

     

     

    myMBP:~ x$ diskutil list

    /dev/disk0

       #:                       TYPE NAME                    SIZE       IDENTIFIER

       0:      GUID_partition_scheme                        *750.2 GB   disk0

       1:                        EFI                         209.7 MB   disk0s1

       2:                  Apple_HFS MACMAIN                 548.0 GB   disk0s2

       3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3

       4:       Microsoft Basic Data BOOTCAMP                201.3 GB   disk0s4

    Gregorys-MacBook-Pro:~ greg$

  • 5. Re: Windows 7 Bootcamp MBR has gone AWOL. Any ideas on getting it back?
    Christopher Murphy Level 3 Level 3 (525 points)

    Yes the hybrid MBR has been replaced with a protective MBR, so the hybrid MBR needs to be recreated. The tool I use to do this is GPT fdisk from sourceforge, download and install that. The basic command to get into interactive edit mode is:

     

    sudo gdisk /dev/rdisk0

     

    You'll need to familiarize yourself with navigating the program.

     

    What you're looking for is the recovery menu, and within that menu is an option to create a new hybrid MBR. You want partitions 2 3 4 added to the MBR, and when it asks, you want the EFI GPT partition first in the MBR, so that's a yes. And when it asks for MBR hex code, just hit enter to accept the default value suggested, and when it asks if you should make that partition bootable say no except for the last one, partition 4 which is for BOOTCAMP, you want that one marked bootable.

     

    Write out the new partition maps, and reboot.