johnheino

Q: iMac with bootcamp only starts W'10

I have  used Bootcamp to install W'10 on  my iMac (El Capitan, 2012)

It worked correctly, although I did not see the Bootcamp-icon in the Windows sys tray.

 

 

Until recently I could change the operating system by pressing the ' Option'  key when the IMac started.

But know, it doesn't react to any key pressed during the booting.

It is always booting to W'10.

 

In Windows, I also can/t see the OS-x disk in the Windows explorer.

So it looks like Windows has changed the MBR, disabling all OS-x options.

 

how can I resolve this?

iMac, iOS 9.2

Posted on Dec 24, 2015 12:56 PM

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Q: iMac with bootcamp only starts W'10

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  • by Loner T,

    Loner T Loner T Dec 24, 2015 1:25 PM in response to johnheino
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    Safari
    Dec 24, 2015 1:25 PM in response to johnheino

    Can you post the output of the following Terminal commands?

     

    diskutil list

    diskutil cs list

    sudo gpt -vv -r show /dev/disk0

    sudo fdisk /dev/disk0

     

    The "sudo" commands will prompt for your password, and it will not be echoed back. You may also see a warning about improper use of "sudo" and potential data loss due to "abuse" of the command.

  • by johnheino,

    johnheino johnheino Dec 24, 2015 1:34 PM in response to Loner T
    Level 1 (0 points)
    Dec 24, 2015 1:34 PM in response to Loner T

    Where do I enter the commands?

    System is booting directly into Windows and diskutil is not recognized as a program..

  • by Loner T,

    Loner T Loner T Dec 24, 2015 1:39 PM in response to johnheino
    Level 7 (24,202 points)
    Safari
    Dec 24, 2015 1:39 PM in response to johnheino

    Ah! Shutdown your Mac, power it back up and run the following two procedures

     

    Resetting the System Management Controller (SMC) on your Mac - Apple Support

    How to Reset NVRAM on your Mac - Apple Support

     

    Now test switching between OSes.

     

    Please also see Boot Camp: Set the default operating system

     

    If you have Windows Automatic Update enabled, you can run into driver issues, which may have corrupted your Apple drivers. Was the Restart OS X item in the System Tray available at any point?

  • by johnheino,

    johnheino johnheino Dec 24, 2015 2:15 PM in response to Loner T
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    Dec 24, 2015 2:15 PM in response to Loner T

    Tried both, no change.

    Seems like Windows disabled OS-X boot options.

    I saw the icon the first few times, but not lately.

    Therefor I used the <Option> during power up to change to OS-X

    But this is not working anymore.

    Looks like a got a Windows-only machine....

  • by Loner T,

    Loner T Loner T Dec 24, 2015 2:51 PM in response to johnheino
    Level 7 (24,202 points)
    Safari
    Dec 24, 2015 2:51 PM in response to johnheino

    Please download GPT Fdisk from http://sourceforge.net/projects/gptfdisk/ and install it on Windows side. In the following example, Gdisk binaries are in the Downloads directory. You can run a CMD window with Admin privileges and enter "gdisk32.exe 0:" without the quotes and post the output of the 'p'(rint) command. You can also use gdisk64.exe the same way.

     

    W8.1-GPTFdisk.PNG

  • by johnheino,

    johnheino johnheino Dec 25, 2015 1:59 AM in response to Loner T
    Level 1 (0 points)
    Dec 25, 2015 1:59 AM in response to Loner T

    screenshot.JPG

  • by Loner T,

    Loner T Loner T Dec 25, 2015 5:27 AM in response to johnheino
    Level 7 (24,202 points)
    Safari
    Dec 25, 2015 5:27 AM in response to johnheino

    This looks normal. Can you go to Recovery Menu ('r') and print the MBR ('o')?

  • by johnheino,

    johnheino johnheino Dec 25, 2015 1:29 PM in response to Loner T
    Level 1 (0 points)
    Dec 25, 2015 1:29 PM in response to Loner T

    You mean the recovery menu when starting up the computer ?

    Pressing keys during startup doesn't work, else I would also be able to select the boot-menu....

     

    I have wireless keyboard, can it be that it is detected too late?

  • by Loner T,

    Loner T Loner T Dec 25, 2015 4:07 PM in response to johnheino
    Level 7 (24,202 points)
    Safari
    Dec 25, 2015 4:07 PM in response to johnheino

    No, the 'r' menu in Gdisk.

     

    GPT fdisk (gdisk) version 1.0.0

     

    Warning: Devices opened with shared lock will not have their

    partition table automatically reloaded!

    Partition table scan:

      MBR: hybrid

      BSD: not present

      APM: not present

      GPT: present

     

    Found valid GPT with hybrid MBR; using GPT.

     

    Command (? for help): r

     

    Recovery/transformation command (? for help): o

     

    Disk size is 1954210120 sectors (931.8 GiB)

    MBR disk identifier: 0x028A47A7

    MBR partitions:

     

    Number  Boot  Start Sector   End Sector   Status      Code

       1                     1       409639   primary     0xEE

       2                409640   1449034287   primary     0xAF

       3            1449034288   1450303823   primary     0xAB

       4      *     1450305536   1954209791   primary     0x07

     

  • by johnheino,

    johnheino johnheino Dec 26, 2015 2:26 AM in response to Loner T
    Level 1 (0 points)
    Dec 26, 2015 2:26 AM in response to Loner T

    Ok, see below...

     

     

    screenshot2.JPG

  • by Loner T,

    Loner T Loner T Dec 26, 2015 7:41 AM in response to johnheino
    Level 7 (24,202 points)
    Safari
    Dec 26, 2015 7:41 AM in response to johnheino

    1. If Windows fails to load BT drivers or the pairing with your Keyboard is corrupted, you can try a wired keyboard, if possible.

    2. Your partitions look to be intact.

    3. Are you able to boot into Local Recovery (Command+R) or Internet Recovery (Command+Opt+R) when powering up your Mac?

    4. Can you try the SMC/NVRAM reset and test?

    5. Can you run Windows Update (do not update any drivers), and then run Apple Software Update and check if your System Tray and Control Panel get the Apple Bootcamp and related icons?

  • by johnheino,

    johnheino johnheino Dec 27, 2015 5:13 AM in response to Loner T
    Level 1 (0 points)
    Dec 27, 2015 5:13 AM in response to Loner T

    1) I don't have other MAC keyboard, only Windows. But then I miss the Option and Command keys...

    2) partitions seem to be ok, but  wonder about what is IN the partitions.... see screenshot from Windows disk management , partitions with 100% free space

     

    windows diskmanagement.JPG

     

    3) Both not possible

    4) Tries it, doesn't change behavior

    5) No updates , everything up-to-date. And nothing to find about Apple Bootcamp in Windows.

     

    So seems like Windows messed up the whole system?

  • by Loner T,

    Loner T Loner T Dec 27, 2015 7:35 AM in response to johnheino
    Level 7 (24,202 points)
    Safari
    Dec 27, 2015 7:35 AM in response to johnheino

    Please install OS X on an external disk, if possible, using How to install OS X on an external drive connected to your Mac - Apple Support and try to boot from the external disk.

  • by johnheino,

    johnheino johnheino Jan 31, 2016 3:54 AM in response to Loner T
    Level 1 (0 points)
    Jan 31, 2016 3:54 AM in response to Loner T

    Problem is still not solved...

    How can I install Os-X on an external disk if I can't get into Os-X on my IMAC?

    When I use my Mac-Mini to create a external disk, it works correctly on my MacMini.

    But on the iMac that is always booting Windows, it doesn't boot from the USB-stick.

     

    I tried a USB-keyboard, but still can't get in recovery (Command-R). System is always starting Windows.

    Seems like Windows corrupted the boot-sector ??

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