Scotch_Brawth
Level 3 (820 points)

Q: 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:

/___sbsstatic___/migration-images/190/19047693-1.png

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

by Christopher Murphy,Solvedanswer
Christopher Murphy Christopher Murphy
Level 3 (555 points)
A:

sudo gdisk /dev/disk0

 

If you get any error messages at this point, report the error messages, don't proceed further.

 

You're now in gdisk interactive mode. Menus/commands are single characters followed by return/enter. So type ? and <enter> and you'll get the main menu listing commands. Type p <enter> and it will print (display) the current GPT. Since you have 5 GPT entries, you can't use a 1 for 1 GPT to MBR scheme like Apple does. The following suggestion is safe, but all hybrid MBRs are non-standard inventions, and therefore I can't tell you how Boot Camp Assistant or Disk Utility will react to this hybrid MBR should you decide to make changes later. What I can tell you is Windows, Linux, and Mac OS X themselves have no problem with this MBR scheme.

 

r <enter>        go to the recovery & transformation menu

h <enter>        create a new hybrid MBR

5 <enter>        add partion 5 to the MBR

<enter>          accept the default MBR hex code of 07

y <enter>        set the bootable flag

n <enter>        do not protect more partitions

o < enter>       print (display) the MBR

 

You should have two entries. One type EE, one 07, with the 07 entry marked with * under Boot. If you don't, report back. If you do, write out the update partition information, and hope  a power failure doesn't occur for the next few seconds...

 

w <enter>     write partition table to disk

 

reboot. hold down option - you should be able to boot into either Mac HD, Recovery HD, or Windows.

 

I just tested this same five partition GPT and 2 partition MBR on a working system and the instructions above worked.

 

Note, so long as CSM-BIOS and thus MBR are required for Boot Camp instead of EFI booting Windows, we're stuck with flaky MBR problems, as well as the 2TB disk limitation for Windows boot disks.

 

Also, I filed bug ID 11980880 at bugreport.apple.com and referenced this thread.

Posted on Jul 28, 2012 12:35 PM

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Q: Repairing Boot Camp after creating new partition

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  • by Number88,

    Number88 Number88 Dec 29, 2013 2:00 PM in response to Number88
    Level 3 (750 points)
    Dec 29, 2013 2:00 PM in response to Number88

    If you go down the testdisk route you should be looking for a NTFS partition that starts at sector 1956108368 and ends at sector 3779479551  (I think). If you find that you can recover it and it should be seen in Windows - perhaps.

    Or at least that recovered partition could be added to the MBR (at the expense of the OSX recovery HD, perhaps).

  • by Loner T,

    Loner T Loner T Dec 29, 2013 2:05 PM in response to Number88
    Level 7 (24,825 points)
    Safari
    Dec 29, 2013 2:05 PM in response to Number88

    JuliusMD... Do you recall if you made it NTFS or FAT? Was this partition included in a backup somewhere?

     

    Number88... More than likely it is NTFS. Testdisk should help.

  • by JuliusMD,

    JuliusMD JuliusMD Dec 29, 2013 2:50 PM in response to Loner T
    Level 1 (0 points)
    Dec 29, 2013 2:50 PM in response to Loner T

    Yes, it is NTFS. No, it was not included in a backup.

     

    What is the testdisk?

  • by Number88,

    Number88 Number88 Dec 29, 2013 2:53 PM in response to JuliusMD
    Level 3 (750 points)
    Dec 29, 2013 2:53 PM in response to JuliusMD

    Testdisk is a free partition recovery utility. It may be able to recover your missing NTFS partition and once recovered it can be entered into your MBR and, hopefully, usable again.

    http://www.cgsecurity.org/wiki/TestDisk_Step_By_Step

  • by Loner T,

    Loner T Loner T Dec 29, 2013 5:18 PM in response to JuliusMD
    Level 7 (24,825 points)
    Safari
    Dec 29, 2013 5:18 PM in response to JuliusMD

    OS X NTFS driver is a read-only driver (unless modified explicitly). Using this piece of information, I would suggest creating/updating a new partition (using gdisk) at start/size (1956108368/1823371184) and making it the same partition-type guid as Microsoft Basic Data (EBD0A0A2-B9E5-4433-87C0-68B6B72699C7) id 0x07. It should be mountable via Disk Utility (or diskutil) and Finder can show files in such a partition. If required, the dd command (man dd) can be used to dump this data to another available external disk drive or a file, if space is available locally.

  • by Loner T,

    Loner T Loner T Dec 29, 2013 7:02 PM in response to Loner T
    Level 7 (24,825 points)
    Safari
    Dec 29, 2013 7:02 PM in response to Loner T

    Here is an example...

     

    bootcamp-ro.png

  • by JuliusMD,

    JuliusMD JuliusMD Dec 30, 2013 3:40 PM in response to Number88
    Level 1 (0 points)
    Dec 30, 2013 3:40 PM in response to Number88

    Ok, thanks. I am doing the testdisk thing but it is taking realy long (over 8 hours now).

     

    At the moment it is at this stage:

     

    Capture.PNG

  • by Number88,

    Number88 Number88 Dec 30, 2013 4:58 PM in response to JuliusMD
    Level 3 (750 points)
    Dec 30, 2013 4:58 PM in response to JuliusMD

    What partition type did you choose to look for? EFI-GPT or Mac?

    You need to look for a NTFS partition type which would be Intel type, I would imagine.

  • by JuliusMD,

    JuliusMD JuliusMD Dec 31, 2013 5:43 AM in response to Number88
    Level 1 (0 points)
    Dec 31, 2013 5:43 AM in response to Number88

    oh, yes, I did use EFI. Now I did a Intel run and this is the result. Still something missing (The total doesn't fit. I have 2000 GB, but in the listing are only 1000GB, 6xxMB, 2xxGB, 65GB).

     

    So now I will do a deeper search (I think I created the missing partition as FAT and later changed it to NTFS).

     

    testdisk.PNG

  • by Loner T,

    Loner T Loner T Dec 31, 2013 6:08 AM in response to JuliusMD
    Level 7 (24,825 points)
    Safari
    Dec 31, 2013 6:08 AM in response to JuliusMD

    JuliusMD wrote:

     

    Still something missing (The total doesn't fit. I have 2000 GB, but in the listing are only 1000GB, 6xxMB, 2xxGB, 65GB).

     

    2,000,000,000,000 / (1024 * 1024 * 1024) = 1862.645 GiB

    I think you have everything covered.

  • by JuliusMD,

    JuliusMD JuliusMD Dec 31, 2013 6:57 AM in response to Loner T
    Level 1 (0 points)
    Dec 31, 2013 6:57 AM in response to Loner T

    I was talking about GB and not GiB and I wrote 600MB not GB as you can see in the much smaller size in sectors. This is probably the 10.9 recovery partition.

     

    I think I created the partion 3 as FAT 200GB under OSX which wrote it inside of GPT.

     

    Then I changed it under windows to a much bigger size and reformated into NTFS which only changed the MBR.

     

    After the update to 10.9 the GPT overwrote the MBR and now it is thinking that I have a 2xxGB FAT but in reality I have a much bigger (9xxGB) NTFS.

  • by JuliusMD,

    JuliusMD JuliusMD Dec 31, 2013 7:23 AM in response to JuliusMD
    Level 1 (0 points)
    Dec 31, 2013 7:23 AM in response to JuliusMD

    I am beginnin to realize that the addition of the 10.9 recovery partition could be problematic to me.

     

    Be cause that means that not only the MBR was overwritten by GPT but the partitioning was really altered.

     

    And depending on the positioning of the recovery partition it could affect the data on the missing 900GB NTFS partition.

  • by Number88,

    Number88 Number88 Dec 31, 2013 8:40 AM in response to JuliusMD
    Level 3 (750 points)
    Dec 31, 2013 8:40 AM in response to JuliusMD

    It may be that as the larger 900GB NTFS partition was only visible to the MBR (not GPT) the 10.9 installer viewed some of this partition as free space and installed the 10.9 recovery partition in its place.

    I honestly don't know, but I fear your Windows system is gone.

    It would be interesting to see what Christopher Murphy thinks of your situation. He knows about these things and is probably the best person to advise.

  • by Loner T,

    Loner T Loner T Dec 31, 2013 11:47 AM in response to JuliusMD
    Level 7 (24,825 points)
    Safari
    Dec 31, 2013 11:47 AM in response to JuliusMD

    Prior to the 10.9 upgrade, do you recall having an OS X Recovery partition? (The assumption is that you upgraded from Lion or Mountain Lion - both should have a Recovery HD).

  • by Number88,

    Number88 Number88 Dec 31, 2013 11:52 AM in response to Loner T
    Level 3 (750 points)
    Dec 31, 2013 11:52 AM in response to Loner T

    True, but if you are struggling to keep within a 4 partition limit the recovery HD is often the first to go.

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