RTbrain
Level 1 (4 points)
Mac OS X

Q: Bootcamp Assistant Issues

Hey all,

 

I own a 27in iMac (late 2012), running Yosemite 10.10.5 with a 3TB drive.  I'm trying to install Windows 7 on a partition using BootCamp Assistant 5.1.4.

 

I keep getting the following message, "The startup disk cannot be partitioned or restored to a single partition."

 

Disk Utility normally only sees the single partition, but when I turn on debugging via Terminal, it DOES see TWO other partitions – EFI Partition and a Recovery HD Partition.

 

How do I proceed? I HAVE fully backed up via Time Machine.  Is it safe to delete the two other partitions? Is there a way to continue and KEEP those partitions intact?  I don't want to handicap any of the Mac's abilities to recover itself after a crash. This is a work machine

 

Thanks in advance

Posted on Aug 20, 2016 8:46 AM

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RTbrain

Q: Bootcamp Assistant Issues

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  • by RTbrain,

    RTbrain RTbrain Aug 22, 2016 10:54 AM in response to Loner T
    Level 1 (4 points)
    Mac OS X
    Aug 22, 2016 10:54 AM in response to Loner T

    I tried and experiment.

     

    I created a 500GB Fat32 partition.
    I had all of my apple bootcamp files on a thumbdrive so I could install them later.

    I booted from a Win7 CD and began an installation on the 500GB partition.

    I got an error message saying the drive needed to be formatted NTFS, so I tried formatting the drive. 
    It worked but I got a second message saying Windows could not install because it was a GPT partition.

     

    I guess it needs to be a MBR partition?  Is THAT what BCA is SUPPOSED to be doing for me?

     

    The "options" seems greyed out in Disk U, so I can't choose what partition map scheme to use.

  • by Loner T,

    Loner T Loner T Aug 22, 2016 10:59 AM in response to RTbrain
    Level 7 (23,633 points)
    Safari
    Aug 22, 2016 10:59 AM in response to RTbrain

    RTbrain wrote:

     

    I guess it needs to be a MBR partition?  Is THAT what BCA is SUPPOSED to be doing for me?

    Yes. BCA also creates the appropriate MBR to allow a legacy BIOS/MBR installation. The 500GB should be within the first 2TB disk blocks on the disk.

  • by RTbrain,

    RTbrain RTbrain Aug 22, 2016 12:02 PM in response to Loner T
    Level 1 (4 points)
    Mac OS X
    Aug 22, 2016 12:02 PM in response to Loner T

    Christines-iMac:~ christinewright$ diskutil list

    /dev/disk0

       #:                       TYPE NAME                    SIZE       IDENTIFIER

       0:      GUID_partition_scheme                        *3.0 TB     disk0

       1:                        EFI EFI                     209.7 MB   disk0s1

       2:                  Apple_HFS Macintosh HD            1.5 TB     disk0s2

       3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3

       4:       Microsoft Basic Data BOOTCAMP                1.5 TB     disk0s5

    Christines-iMac:~ christinewright$

    Christines-iMac:~ christinewright$ sudo fdisk /dev/disk0

  • by Loner T,

    Loner T Loner T Aug 22, 2016 12:11 PM in response to RTbrain
    Level 7 (23,633 points)
    Safari
    Aug 22, 2016 12:11 PM in response to RTbrain

    Can you post the output of the Fdisk command?

  • by RTbrain,

    RTbrain RTbrain Aug 22, 2016 12:26 PM in response to Loner T
    Level 1 (4 points)
    Mac OS X
    Aug 22, 2016 12:26 PM in response to Loner T

    Disk: /dev/disk0    geometry: 97451/255/63 [1565565872 sectors]

    Signature: 0xAA55

             Starting       Ending

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

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

    1: EE 1023 254  63 - 1023 254  63 [         1 - 4294967294] <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 

  • by Loner T,

    Loner T Loner T Aug 22, 2016 12:32 PM in response to RTbrain
    Level 7 (23,633 points)
    Safari
    Aug 22, 2016 12:32 PM in response to RTbrain

    The MBR is invalid. We should create one manually. Are you familiar with GPT Fdisk - https://sourceforge.net/projects/gptfdisk/ ? Can you install it and we can then use it to create a MBR, before you attempt the next iteration?

  • by RTbrain,

    RTbrain RTbrain Aug 22, 2016 12:54 PM in response to Loner T
    Level 1 (4 points)
    Mac OS X
    Aug 22, 2016 12:54 PM in response to Loner T

    Not familiar.  Question though, would I be changing BOTH partitions to MBR or would it allow me to just change the BOOTCAMP partition to MBR and leave the main one as GPT?

  • by Loner T,

    Loner T Loner T Aug 22, 2016 1:06 PM in response to RTbrain
    Level 7 (23,633 points)
    Safari
    Aug 22, 2016 1:06 PM in response to RTbrain

    We are not changing your disk from GPT to MBR. We are going to overlay an MBR (called a Hybrid MBR) on top of the GPT to let the windows installer think that it is a MBR disk.

     

    Once you have GPT Fdisk installed, from Terminal, you will need to run the following steps.

     

    Rebuild MBR to match the new GPT information thus resetting the Hybrid MBR. Use defaults for other questions (like partition codes). The only values that need modifications are the Boot flags and step 10. Accept all other defaults that Gdisk offers. Please see the sample Q&A as an example. These steps can be repeated if you make a mistake before you get to Step 12, otherwise start from Step 1 for these steps. Step 6 has numbers which are typed with a space between the numbers. Please see the sample Q&A before you execute these steps.

    1. Sudo gdisk /dev/rdisk0
    2. P  (Print list of parts)
    3. R  (Recover)
    4. O (print current Hybrid MBR)
    5. H (chooses Hybrid)
    6. Partitions numbers to be hybridized: 2 3 4
    7. Y  (Good for GRUB question)
    8. N  (part 2 boot flag)
    9. N  (part 3 boot flag)
    10. Y  (part 4 boot flag make NTFS bootable partition)
    11. O  (print current Hybrid MBR)
    12. W (Write the new MBR)
    13. Y (Yes! write the new MBR)
    14. Reboot

     

    Here is sample Q&A for this section. Please notice the Press Enter/Return.

     

    Place EFI GPT (0xEE) partition first in MBR (good for GRUB)? (Y/N): Y

     

    Creating entry for GPT partition #2 (MBR partition #2)

    Enter an MBR hex code (default AF): Press Enter/Return

    Set the bootable flag? (Y/N): N

     

    Creating entry for GPT partition #3 (MBR partition #3)

    Enter an MBR hex code (default AB): Press Enter/Return

    Set the bootable flag? (Y/N): N

     

    Creating entry for GPT partition #4 (MBR partition #4)

    Enter an MBR hex code (default 07): Press Enter/Return

    Set the bootable flag? (Y/N): Y

  • by RTbrain,

    RTbrain RTbrain Aug 23, 2016 5:36 AM in response to RTbrain
    Level 1 (4 points)
    Mac OS X
    Aug 23, 2016 5:36 AM in response to RTbrain

    Wow. Thank you. I'm going to have to put this on hold for a bit. I'll have to revisit this later.  I'll keep you posted.

  • by Loner T,

    Loner T Loner T Aug 23, 2016 6:00 AM in response to RTbrain
    Level 7 (23,633 points)
    Safari
    Aug 23, 2016 6:00 AM in response to RTbrain

    Please see http://www.rodsbooks.com/gdisk/hybrid.html , if you suffer from insomnia.

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