Daniel miller

Q: El Cap won't dual boot Windows 8.1 w/ EFI

I have a 2009 Mac Pro. Upgraded the procs to dual x5690 and "flashed" it to read as a 5,1. Running a GTX 980 and Quadro K4000. 64 Gb ram. OSX installed on a owc pcie ssd, Windows installed on Samsung 850 pro plugged into spare sata connector in optical bay.

 

 

My quandary: I was running Yosemite and Windows 8.1 in harmony. Each one on its own drive, not two partitions of the same drive. I upgraded to El Cap. I could no longer boot into Windows if my El Cap drive was plugged in. I did some research and saw that El Cap doesn't like MBRs so I did a clean install of Windows after switching it over to EFI but it still won't boot. I use startup disk utility, and it reboots and just sits on a black screen.

 

 

Is there a way to get this sorted? Do I have to disable this new SIP feature that seems to be wreaking havoc on all sorts of folks? Help me Obi-Wan Kenobi....

Mac Pro, OS X El Capitan (10.11.1), Windows 8.1

Posted on Dec 11, 2015 9:51 AM

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Q: El Cap won't dual boot Windows 8.1 w/ EFI

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  • by Loner T,

    Loner T Loner T Dec 14, 2015 3:16 PM in response to Daniel miller
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    Dec 14, 2015 3:16 PM in response to Daniel miller

    BCD is Windows Boot Configuration Data. It contains structures needed by Windows to boot. Your EFI Boot is the Windows EFI booter, which is normal. If it boots properly, then your Windows installation is fine.

     

    Please see Can't resize Macintosh HD partition to see the commands used to mount EFI and look inside on the structures in each EFI.

     

    What type of error can you recall during Windows boot/installation?

  • by Daniel miller,

    Daniel miller Daniel miller Dec 14, 2015 3:39 PM in response to Loner T
    Level 1 (5 points)
    Dec 14, 2015 3:39 PM in response to Loner T

    I would select the Primary partition and select next. It would tell me Windows could not be installed, see the log. I looked at the log, and noticed that the installer was scanning all the partitions of all the drives mounted, and telling me that most of them were too small to install windows on and that others did not have an EFS file system. I couldn't imagine why it would look at disks other than the one I selected in the menu, so I pulled the drive to make it look where I wanted it to.

     

    In the EFI structure there are 3 folders listed below with the sub folder/files in them:

    Apple > Extensions > Firmware.scap

    Boot > bootx64.efi

    Microsoft > Boot > (Many Folders that seem to be related to language support) & BCD, boot.stl, bootmgfw.efi, bootmgr.efi, memtest.efi

  • by Loner T,

    Loner T Loner T Dec 14, 2015 3:44 PM in response to Daniel miller
    Level 7 (24,307 points)
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    Dec 14, 2015 3:44 PM in response to Daniel miller

    Daniel miller wrote:

     

    I would select the Primary partition and select next. It would tell me Windows could not be installed, see the log. I looked at the log, and noticed that the installer was scanning all the partitions of all the drives mounted, and telling me that most of them were too small to install windows on and that others did not have an EFS file system. I couldn't imagine why it would look at disks other than the one I selected in the menu, so I pulled the drive to make it look where I wanted it to.

    This is a known issue on a Mac with multiple drives. Usually, scrolling the disk list in the Windows Installer should provide the disk you want.

     

    Microsoft > Boot > (Many Folders that seem to be related to language support) & BCD, boot.stl, bootmgfw.efi, bootmgr.efi, memtest.efi

    Does the Microsoft folder exist on both disks (Windows-only and OSX-only disks)?

  • by Daniel miller,

    Daniel miller Daniel miller Dec 14, 2015 3:55 PM in response to Loner T
    Level 1 (5 points)
    Dec 14, 2015 3:55 PM in response to Loner T

    Loner T wrote:


    This is a known issue on a Mac with multiple drives. Usually, scrolling the disk list in the Windows Installer should provide the disk you want.

    I would select the Primary partition from the disk I wanted. I just wasn't clear on why the installer ignored that selection and scanned all mounted portions any way.

     

    Loner T wrote:

     

    Does the Microsoft folder exist on both disks (Windows-only and OSX-only disks)?

    It appears that the Windows EFI folder is empty... I guessing the rub lies somewhere in there?

  • by Loner T,

    Loner T Loner T Dec 14, 2015 4:08 PM in response to Daniel miller
    Level 7 (24,307 points)
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    Dec 14, 2015 4:08 PM in response to Daniel miller

    The simplest method is to download EasyBCD - https://neosmart.net/wiki/easybcd/ and check where the current BCD points to.

  • by Daniel miller,

    Daniel miller Daniel miller Dec 14, 2015 4:23 PM in response to Loner T
    Level 1 (5 points)
    Dec 14, 2015 4:23 PM in response to Loner T

    When I open up the program, this is displayed in the text window.

     

    There is one entry in the Windows bootloader.

     

     

    Default: Windows 8.1

    Timeout: 30 seconds

    EasyBCD Boot Device: C:\

     

     

    Entry #1

    Name: Windows 8.1

    BCD ID: {current}

    Drive: C:\

    Bootloader Path: \Windows\system32\winload.efi

     

    Is this the relevant info?

  • by Loner T,

    Loner T Loner T Dec 14, 2015 6:08 PM in response to Daniel miller
    Level 7 (24,307 points)
    Safari
    Dec 14, 2015 6:08 PM in response to Daniel miller

    Can you check the physical path that C: points to?

  • by Daniel miller,

    Daniel miller Daniel miller Dec 14, 2015 6:21 PM in response to Loner T
    Level 1 (5 points)
    Dec 14, 2015 6:21 PM in response to Loner T

    Man, Im sorry to be such a pain in the ***, but how do I do that? I googled and everyone had a different method and Im not sure if any of them are exactly what it is youre looking for. Oerhaps tangentially, I did switch over to verbose mode in EasyBCD and it showed some more details.

     

     

    Windows Boot Manager

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

    identifier              {9dea862c-5cdd-4e70-acc1-f32b344d4795}

    device                  partition=\Device\HarddiskVolume4

    path                    \EFI\Microsoft\Boot\bootmgfw.efi

    description             Windows Boot Manager

    locale                  en-US

    inherit                 {7ea2e1ac-2e61-4728-aaa3-896d9d0a9f0e}

    integrityservices       Enable

    default                 {dcfbd22c-a2da-11e5-9795-f679be082bde}

    resumeobject            {dcfbd22b-a2da-11e5-9795-f679be082bde}

    displayorder            {dcfbd22c-a2da-11e5-9795-f679be082bde}

    toolsdisplayorder       {b2721d73-1db4-4c62-bf78-c548a880142d}

    timeout                 30

     

     

    Windows Boot Loader

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

    identifier              {dcfbd22c-a2da-11e5-9795-f679be082bde}

    device                  partition=C:

    path                    \Windows\system32\winload.efi

    description             Windows 8.1

    locale                  en-US

    inherit                 {6efb52bf-1766-41db-a6b3-0ee5eff72bd7}

    recoverysequence        {dcfbd22d-a2da-11e5-9795-f679be082bde}

    integrityservices       Enable

    recoveryenabled         Yes

    isolatedcontext         Yes

    allowedinmemorysettings 0x15000075

    osdevice                partition=C:

    systemroot              \Windows

    resumeobject            {dcfbd22b-a2da-11e5-9795-f679be082bde}

    nx                      OptIn

    bootmenupolicy          Standard

  • by Loner T,

    Loner T Loner T Dec 14, 2015 7:18 PM in response to Daniel miller
    Level 7 (24,307 points)
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    Dec 14, 2015 7:18 PM in response to Daniel miller

    Run a CMD window with Administrative privileges and use diskpart to find which disk/partition is assigned the letter C:.

     

    Please see the command syntax in https://technet.microsoft.com/en-us/library/cc766465%28v=ws.10%29.aspx?f=255&MSP PError=-2147217396 .

     

    W8.1-Gdisk-BCD.PNG

  • by Daniel miller,

    Daniel miller Daniel miller Dec 14, 2015 10:57 PM in response to Loner T
    Level 1 (5 points)
    Dec 14, 2015 10:57 PM in response to Loner T

    Disk 1 Partition 3

     

    diskpart.PNG

  • by Loner T,

    Loner T Loner T Dec 15, 2015 4:00 AM in response to Daniel miller
    Level 7 (24,307 points)
    Safari
    Dec 15, 2015 4:00 AM in response to Daniel miller

    This points back to

       673792   999540736      3  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

    but we are interested in

    device                  partition=\Device\HarddiskVolume4

    path                    \EFI\Microsoft\Boot\bootmgfw.efi

    If this is a new installation, it may be easier to re-install with both disks connected, and address any issues. If the Microsoft folder is on one of the disks, but not the other, that is the one in use. Based on this entry, Volume4 is the non-OSX disk, which causes the OS X volume not be able to boot Windows.

  • by Daniel miller,

    Daniel miller Daniel miller Dec 18, 2015 8:56 PM in response to Loner T
    Level 1 (5 points)
    Dec 18, 2015 8:56 PM in response to Loner T

    Sorry, was out of pocket for a few days. Back at my machine, still trying to get this sorted. It seems that with the OS X drive plugged in, it will does not want to install.

     

    Steps:

    1) Format drive in Disk Utility to OS X Journaled, with GUID partition table.

    2) Boot from Windows Installer thumb drive (created by BCA)

    3) Check size of EFI partition in the Windows Installer (I matches the size of the EFI partition on my OS X drive)

    4) Select the HFS formatted partition and delete it

    5) Select the new "Unallocated Disk Space" and hit "New"

     

    :: this is where things are different with the OS X drive plugged in

    When I did the install that worked, I did step 1, then unplugged the OS X drive. Then followed the rest of the steps. When I hit "New" it made an MSR partition and a Primary partition. Windows installed flawlessly.


    With the OS X drive plugged in, when I hit "New" the installer makes ANOTHER EFI partition this time, and its smaller. It also creates the MSR partition and the Primary Partition.


    6) Select "Primary Partition" and hit "next"


    The installer tells me it can't install windows on this drive, see set up logs.

    I snapped a photo of the install log after

    IMG_0036_scaled.jpg

  • by Loner T,

    Loner T Loner T Dec 18, 2015 9:13 PM in response to Daniel miller
    Level 7 (24,307 points)
    Safari
    Dec 18, 2015 9:13 PM in response to Daniel miller

    Test 1 - In step 4, instead of HFS, use Disk Utility to make it Free Space. In step 5, do not use New. Select the Free Space and click on Next.

    Test 2 - Leave the disk as an unformatted disk and let the Windows Installer use the entire disk. The Windows default EFI is 104.9 MB, Macs' DU creates a 200MB EFI.

  • by Daniel miller,

    Daniel miller Daniel miller Dec 18, 2015 10:46 PM in response to Loner T
    Level 1 (5 points)
    Dec 18, 2015 10:46 PM in response to Loner T

    Loner T wrote:

     

    Test 1 - In step 4, instead of HFS, use Disk Utility to make it Free Space. In step 5, do not use New. Select the Free Space and click on Next.

    No dice, same problem.

     

    Loner T wrote:

     

    Test 2 - Leave the disk as an unformatted disk and let the Windows Installer use the entire disk. The Windows default EFI is 104.9 MB, Macs' DU creates a 200MB EFI.

    Some progress, Windows installed fine, but it STILL won't boot from OS X to Windows using the Start Up disk Utility. It works if I hold Option while booting, but the old functionality just won't work....

     

    I tried to go back to the other thread you linked to look at the EFI partitions, but when I enter the second command in terminal I get:

    mount_msdos: Unsupported sector size (0)

  • by Daniel miller,

    Daniel miller Daniel miller Dec 18, 2015 11:02 PM in response to Daniel miller
    Level 1 (5 points)
    Dec 18, 2015 11:02 PM in response to Daniel miller

    Upon further digging and running the diskutil list disk command. It doesn't look like the windows installer made an EFI partition.

    /dev/disk0 (internal, physical):

       #:                       TYPE NAME                    SIZE       IDENTIFIER

       0:      GUID_partition_scheme                        *512.1 GB   disk0

       1:         Microsoft Reserved                         134.2 MB   disk0s1

       2:       Microsoft Basic Data BOOTCAMP                512.0 GB   disk0s2

     

    This is super frustrating....


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