GPT Error Windows installatie > Bootcamp

Discussion in 'Windows, Linux & Others on the Mac' started by Donstil-nl, Aug 17, 2012.

  1. Donstil-nl, Aug 17, 2012
    Last edited: Aug 17, 2012

    Donstil-nl macrumors 6502

    Donstil-nl

    Joined:
    Jun 27, 2008
    Location:
    Netherlands
    #1
    Dear Forumers.
    I got a problem with Bootcamp and i am hoping one of you can help me?

    I got a MacbookPro okt 2011 i7 2,3/8gb/128gbSSD/500GBHDD and got a problem with Bootcamp and Windows 7 or 8. The installation of Windows 7 (and 8) gives a error because it cannot install on a MBR Formatted HDD because of EFI limitations. I have to install on a GPT formatted drive.

    The problem is i didn't do anything with the HDD in the first place, Bootcamp did.

    This is wat i have done so far.

    1. Install Windows trough the normal Bootcamp app > Gives the GPT Error.
    2. Install rEFIt > Swapped the 500GB Second drive for a New non formatted one > Installed Windows trough the USB Drive without use of Bootcamp > Gives this error "Installation connot change boot and hase to cancel".

    I don't no what to do now, i used a legal Windows 7 disk to make a Iso, downloaded a illegal one, downloaded Windows 8 trough MSDN and downloaded a illegal Windows 8 trough Usenet, nothing works.

    On 10.7 i used Windows 7 trough Bootcamp just fine, now i am on ML And nothing works.

    thnx in advance.

    (sorry for bad english)
     
  2. murphychris macrumors 6502a

    Joined:
    Mar 19, 2012
    #2
    It's complicated, you need to better understand UEFI, BIOS, MBR, and GPT.

    Windows booting UEFI mode requires a GPT only disk.
    Windows booting BIOS mode requires an MBR disk (or hybrid MBR and GPT which it will ignore).

    You somehow managed to boot Windows in UEFI mode, which is not supported yet by Apple. Boot Camp Assistant creates a hybrid MBR on what is already a GPT disk, and that's what's causing the error.

    You either need to boot Windows in CSM (legacy BIOS) mode, and then it will install; or you need to restore the protective MBR (removing the hybrid MBR). The safest way to remove the hybrid MBR is to download and install gdisk, which is a command line only program (no GUI), and learn how to use it. Basically the feature you want is in the Expert menu, type x <enter>; and then you want to create a new protective MBR, type n <enter>; and then write out the new partition map, type w <enter>.

    Don't forget to backup first!
     
  3. Donstil-nl thread starter macrumors 6502

    Donstil-nl

    Joined:
    Jun 27, 2008
    Location:
    Netherlands
    #3
    Thx for the Replay!

    It's indeed the Problem that my Windows 7 (OEM DISK) or Windows 8 (MSDN Download) installation boots in EFI mode.

    But i don't now why, rEFIt let me boot the Bios mode but than i get a BCD error.

    i will try your tips tonight!

    Edit: I got 2 disks in my MBP (1 ssd and one normal drive) so my second drive (normal HDD) can be erased thats no problem (i got a Timemachine backup of it, just to be sure).

    If i got it all fixed, can i read from a MBR disk on MountainLion?
     
  4. murphychris macrumors 6502a

    Joined:
    Mar 19, 2012
    #4
    When booting BIOS mode, operating systems chain load their bootloaders. The BCD error indicates you have a bootloader problem that needs to be repaired using Widows Startup Repair.

    I don't understand the question.

    Mac, Windows, Linux all recognize MBR and GPT disks. Apple's system installers will refuse to install to an MBR disk, although Apple's EFI can boot (Mac OS, Linux, Windows) from an MBR only disk. If the disk is MBR only, it will lack an EFI System partition, and you won't be able to do firmware updates on your computer.
     
  5. Donstil-nl thread starter macrumors 6502

    Donstil-nl

    Joined:
    Jun 27, 2008
    Location:
    Netherlands
    #5
    My english is not always that good :cool: but you did answer my question.

    I am trying gdisk tonight.
     
  6. murphychris macrumors 6502a

    Joined:
    Mar 19, 2012
    #6
    "hybrid MBR" is a (non-standard) modified protective MBR which is created at the time a GPT is created. It's perhaps more clear to call it a hybrid MBR/GPT. A hybrid MBR means you still have a GPT, which is what Mac OS X will honor, and you'll also have an MBR which is what Windows uses on Apple hardware with the CSM (legacy BIOS).

    If you remove the hybrid MBR for a protective MBR (i.e. resulting in a pure GPT disk), you will not be able to boot Windows with the CSM, you'll have to figure out how to get EFI booting to work, and there are at least two threads in Mac Rumors on that procedure, which involves quite a bit of work for Windows 7. But at least when EFI booting, Windows will use the GPT as well instead of this clusterf|ck dual MBR/GPT thing that causes so many people problems.
     
  7. Donstil-nl thread starter macrumors 6502

    Donstil-nl

    Joined:
    Jun 27, 2008
    Location:
    Netherlands
    #7
    Oke i got a new problem now.

    I got the Windows 8 installation disc working in Efi mode. And i converted my drive to GPT Only (My second drive).

    Now i got the Problem that Windows gives a \BCD Error.
    I downloaded a Windows 8 repair disc but that disc won't boot on my MBP (Even trough rEFIt it won't boot, on a normal PC it boots just fine.)
     
  8. murphychris macrumors 6502a

    Joined:
    Mar 19, 2012
    #8
    The Windows 8 installation disk should have repair functions on it, doesn't it? I don't see why there is a need for a separate repair disk. And it's confusing that the Windows 8 installation disk will EFI boot, but the Windows 8 repair disc won't. I think that repair disk is probably CPU architecture specific - Windows does that, you can't just move an installation from one computer to another and expect it to boot.

    Also realize that Apple's EFI is based primarily on Intel EFI 1.10, not UEFI 2.x. Microsoft's minimum system requirements for EFI booting is UEFI 2.x firmware, which thus far Apple hardware doesn't have. So while EFI boot may work in some cases, it's not supportable by either Microsoft or Apple right now.
     

Share This Page