iMac 5k, Boot camp, fusion drive, Windows cannot install, GPT

Question

Hello,I&#x27;m using a iMac 5K that I just purchased last week. I&#x27;m attempting to install windows 8.1 via bootcamp. Bootcamp seems to complete its job without issue, but when I try to install windows on the bootcamp partition I get the following error: "Windows cannot be installed to this disk. The selected disk is of the GPT partition style."I have reviewed a number of threads discussing the GPT partition style and potential fixes. The problem is that I cannot delete the partition from windows or disk utility and simply re-add it. The fusion drive setup won&#x27;t allow it. I&#x27;m not sure how else to resolve the issue.Thank you,

Loner T · Answer

1. Do you have a 3TB Fusion drive or 1TB Fusion Drive?2. You need to delete the Windows partition using BC Assistant only. Any other tool will further aggravate the pain and grief.3. Are you interrupting the Bootcamp process using the Alt/Option key at any point?4. Please ensure that there is no other external storage connected except the USB Installer.5. It is possible that BCA failed to create the proper MBR, which can be corrected.

Isaac da Giraffe · Answer

Thanks for the reply.1. 3TB Fusion drive2. Understood. For whatever reason bootcamp doesn&#x27;t &#x27;see&#x27; its own partition and cant remove it.3.I&#x27;m not interrupting bootcamps process. When bootcamp is finished on the OSX side and the machine reboots, it doesn&#x27;t reboot into the windows side t continue installation. I have to hold down alt and select the windows installation to attempt to continue the process.4. No other external storage is in use on the machine.5. I hope soThank you for the help. I&#x27;m on a bit of a time crunch to solve this.

Loner T · Answer

Can you post the output of the following Terminal commands?diskutil listdiskutil cs listsudo gpt -vv -r show /dev/disk0sudo fdisk /dev/disk0sudo gpt -vv -r show /dev/disk1sudo fdisk /dev/disk1The "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.

Isaac da Giraffe · Answer

Last login: Thu Jul  2 09:33:28 on ttys000Isaacs-iMac:~ isaactest$ diskutil list/dev/disk0   #:                       TYPE NAME                    SIZE       IDENTIFIER   0:      GUID_partition_scheme                        *121.3 GB   disk0   1:                        EFI EFI                     209.7 MB   disk0s1   2:          Apple_CoreStorage                         121.0 GB   disk0s2   3:                 Apple_Boot Boot OS X               134.2 MB   disk0s3/dev/disk1   #:                       TYPE NAME                    SIZE       IDENTIFIER   0:      GUID_partition_scheme                        *3.0 TB     disk1   1:                        EFI EFI                     209.7 MB   disk1s1   2:          Apple_CoreStorage                         2.7 TB     disk1s2   3:                 Apple_Boot Recovery HD             650.0 MB   disk1s3   4:       Microsoft Basic Data                         337.9 GB   disk1s4/dev/disk2   #:                       TYPE NAME                    SIZE       IDENTIFIER   0:                  Apple_HFS Macintosh HD           *2.8 TB     disk2                                 Logical Volume on disk0s2, disk1s2                                 3E6B1B6C-C545-4506-92F9-4EB6D97694E1                                 Unencrypted Fusion Drive/dev/disk3   #:                       TYPE NAME                    SIZE       IDENTIFIER   0:     FDisk_partition_scheme                        *7.7 GB     disk3   1:                 DOS_FAT_32 WININSTALL              7.7 GB     disk3s1Isaacs-iMac:~ isaactest$ diskutil cs listCoreStorage logical volume groups (1 found)|+-- Logical Volume Group 1610A7A0-6BA7-4A02-B478-1FDDDF933C8F    &#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;&#x3D;    Name:         Internal Drive    Status:       Online    Size:         2782855290880 B (2.8 TB)    Free Space:   114688 B (114.7 KB)    |    +-&lt; Physical Volume B5AECBB5-F330-4118-BD8A-7125C9886335    |   ----------------------------------------------------    |   Index:    0    |   Disk:     disk0s2    |   Status:   Online    |   Size:     120988852224 B (121.0 GB)    |    +-&lt; Physical Volume 558DAD92-698A-4033-9AEF-20C99C48AEA8    |   ----------------------------------------------------    |   Index:    1    |   Disk:     disk1s2    |   Status:   Online    |   Size:     2661866438656 B (2.7 TB)    |    +-&gt; Logical Volume Family FE2FD85D-0649-4C34-9EC8-67D27C75106B        ----------------------------------------------------------        Encryption Status:       Unlocked        Encryption Type:         None        Conversion Status:       NoConversion        Conversion Direction:    -none-        Has Encrypted Extents:   No        Fully Secure:            No        Passphrase Required:     No        |        +-&gt; Logical Volume 3E6B1B6C-C545-4506-92F9-4EB6D97694E1            ---------------------------------------------------            Disk:                  disk2            Status:                Online            Size (Total):          2776999919616 B (2.8 TB)            Conversion Progress:   -none-            Revertible:            No            LV Name:               Macintosh HD            Volume Name:           Macintosh HD            Content Hint:          Apple_HFSIsaacs-iMac:~ isaactest$ sudo gpt -vv -r show /dev/disk0WARNING: Improper use of the sudo command could lead to data lossor the deletion of important system files. Please double-check yourtyping when using sudo. Type "man sudo" for more information.To proceed, enter your password, or type Ctrl-C to abort.Password:gpt show: /dev/disk0: mediasize&#x3D;121332826112; sectorsize&#x3D;512; blocks&#x3D;236978176gpt show: /dev/disk0: PMBR at sector 0gpt show: /dev/disk0: Pri GPT at sector 1gpt show: /dev/disk0: Sec GPT at sector 236978175      start       size  index  contents          0          1         PMBR          1          1         Pri GPT header          2         32         Pri GPT table         34          6                  40     409600      1  GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B     409640  236306352      2  GPT part - 53746F72-6167-11AA-AA11-00306543ECAC  236715992     262144      3  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC  236978136          7           236978143         32         Sec GPT table  236978175          1         Sec GPT headerIsaacs-iMac:~ isaactest$ sudo fdisk /dev/disk0Disk: /dev/disk0 geometry: 14751/255/63 [236978176 sectors]Signature: 0xAA55         Starting       Ending #: id  cyl  hd sec -  cyl  hd sec [     start -       size]------------------------------------------------------------------------ 1: EE 1023 254  63 - 1023 254  63 [         1 -  236978175] &lt;Unknown ID&gt; 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      Isaacs-iMac:~ isaactest$ sudo gpt -vv -r show /dev/disk1gpt show: /dev/disk1: mediasize&#x3D;3000592982016; sectorsize&#x3D;512; blocks&#x3D;5860533168gpt show: /dev/disk1: PMBR at sector 0gpt show: /dev/disk1: Pri GPT at sector 1gpt show: /dev/disk1: Sec GPT at sector 5860533167       start        size  index  contents           0           1         PMBR           1           1         Pri GPT header           2          32         Pri GPT table          34           6                   40      409600      1  GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B      409640  5198957888      2  GPT part - 53746F72-6167-11AA-AA11-00306543ECAC  5199367528     1269536      3  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC  5200637064         888           5200637952   659894272      4  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7  5860532224         911           5860533135          32         Sec GPT table  5860533167           1         Sec GPT headerIsaacs-iMac:~ isaactest$ sudo fdisk /dev/disk1Disk: /dev/disk1 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] &lt;Unknown ID&gt; 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      Isaacs-iMac:~ isaactest$

Loner T · Answer

Very interesting that BCA put the Windows partition on the HDD outside the 2TB limit and subsequently failed to create a MBR (which would have been invalid anyway), and then chose to boot using legacy BIOS not EFI.You have two choices.1. Remove the current BC Partition with BCA (only - do not use Disk Utility to manipulate the disks) and allow BCA to create a proper partition and MBR to allow a BIOS-based installation, or,2. Convert GPT4 on the HDD to a Free Space partition and check if EFI Boot will work. It may not work, because the MSR partition is FAT and will have issues when put outside the 2TB boundary.My recommendation is option 1. You do not need to rebuild the USB, just use the BCA option to Restore the disk to single partition and then use the last Option - &#x27;Install...".

Isaac da Giraffe · Answer

If it&#x27;s of interest originally BCA failed causing a rogue 800 gb partition to be formed which I could not fix on my own, so I brought it to an Apple retail store and the staff member used a slurry of terminal commands to remake the Fusion drive into a single partition. I brought the iMac home, tried BCA and that brings us up to the present when I created this thread.Previously when I tried to remove the BCA partition the utility failed. I tried it again and this time I was able to remove the partition, remake it, and install windows without an issue. I thought I&#x27;d provide all this information to satisfy anyone&#x27;s intellectual curiosity. Thank you for your assistance Loner.

Loner T · Answer

Thanks for posting back with your setup. The Apple Genii will usually pull the HDD out of the CS LVG and then erase and re-insert it back into the CS LVG/LV. It usually depends on available space on the SSD and used space in the LV. Glad to see it working.

ccwoodside · Answer

Hey sorry to bother you, I saw that you were helping a lot of people with formatting partitions for a bootcamp bootup. I ran through the process using gdisk but I think i might have messed it up. I was curious if you could help me. I can give you the information rundown from termninal if you just let me know what you need.

Loner T · Answer

Can you start a new discussion? Please also see Find answers and ask new questions .

ccwoodside · Answer

Sure. Here&#x27;s the post2015 iMac Boot Camp not working giving "We couldn&#x27;t create a new partition error..."

Alexau881 · Answer

I had the same problem but thanks to this topic i found decision here.