El Capitan and Bootcamp with Windows 10 (GPT error)

El Cap seems to have nuked my Bootcamp created Windows 10 partition and it won't let me install one outright.


I get the "This is GPT partition style" error, and I'm not sure how to fix it under El Capitan. I know you can use GPT fdisk to repair the GPT/MBR issues but GPT fdisk doesn't work with El Capitan and I'm not sure of any other method to repair the GPT/MBR tables so that the Windows 10 install will work.


I've tried everything at this point. Wiped the SSD, new install of El Capitan and then Bootcamped. Used my now current restore of El Capitan, used Bootcamp, same error. Manually created a partition and then formatted it in the W10 install, same error. No matter what I've done, I get that error now and I have no idea how to fix it without downgrading all the way to Mavericks just to be able to use GPT fdisk to repair things.


But even if I did that, the upgrade to El Capitan is what broke my W10 partition in the first place, and I don't know if I'm willing to downgrade and give up what El Cap offers on the OSX side of things, even though its broken my Windows install and ability to install outright.


Does anyone have any idea how to fix this issue? I found this guide http://macriot.com/mcrt/?p=2362[1] but since GPT fdisk doesn't work with El Capitan, I don't know what else to do.

Replies

Hi ARJ,

Try the following and let me know how it goes...


Boot into Recovery Mode (cmd+R).

  1. Utilities menu > Terminal > Type:

    csrutil disable

  2. Reboot normally


First, download gdisk (sourceforge.net/projects/gptfdisk/files/gptfdisk/1.0.0/gdisk-binaries/gdisk-1.0.0.pkg/download) and run the installer package.

Then run gdisk from a terminal window and run the v (verify command).

  • sudo gdisk /dev/disk0
  • Command (? for help): v


Given what you've said, it'll probably say:


Warning! Mismatched GPT and MBR partition! MBR partition 4, of type 0x07, has no corresponding GPT partition! You may continue, but this condition might cause data loss in the future!

Identified 1 problems!


Next, display the MBR partition table and make note of the start and end sectors for your BOOTCAMP partition.


  • Command (? for help): r
  • Recovery/transformation command (? for help): o

This should be partition 4 unless you've added additional partition(s), which is not officially supported by Boot Camp. It should show something like this:


Disk size is 1953525168 sectors (931.5 GiB)

MBR disk identifier: 0x7C170CB2

MBR partitions:


Number Boot Start Sector End Sector Status Code

1 1 409639 primary 0xEE

2 409640 975693095 primary 0xAF

3 975693096 976962631 primary 0xAB

4 * 976963584 1952806911 primary 0x07


Next, display the GPT partition table information:


  • Recovery/transformation command (? for help): m
  • Command (? for help): p


Number Start (sector) End (sector) Size Code Name

1 40 409639 200.0 MiB EF00 EFI System Partition

2 409640 975693095 465.1 GiB AF00 Customer

3 975693096 976962631 619.9 MiB AB00 Recovery HD

4 976963584 1953523711 465.7 GiB 0700 BOOTCAMP


Compare the start and end sectors for partition 4 to the MBR partition 4 start and end sectors. Most likely the start sectors will match, but the end sectors will be different.


Next, delete the GPT partition 4. (Note: this does not delete the actual partition from disk. It only deletes gdisk's in-memory representation of the GPT).


  • Command (? for help): d
  • Partition number (1-4): 4


Now, create a new partition 4 using the start and end sector values from the MBR partition 4:


  • Command (? for help): n
  • Partition number (4-128, default 4): 4
  • First sector (34-1953525134, default = 976962632) or {+-}size{KMGTP}: 976963584
  • Last sector (976963584-1953525134, default = 1953525134) or {+-}size{KMGTP}: 1952806911
  • Current type is 'Apple HFS/HFS+'
  • Hex code or GUID (L to show codes, Enter = AF00): 0700
  • Changed type of partition to 'Microsoft basic data'


Now, change the name of the new partition 4 to BOOTCAMP:


  • Command (? for help): c
  • Partition number (1-4): 4
  • Enter name: BOOTCAMP


Run the verify command. It should report no problems. If it still reports a problem, quit (q command) and start over.


Command (? for help): v


If everything checks out, write new partition table to disk and exit.


Command (? for help): w


Reboot and test your dual boot setup to verify all is working correctly.


Boot back into Recovery Mode (cmd+R).

  1. Utilities menu > Terminal > Type:

    csrutil enable

  2. Reboot normally


-Max.

I tried your method Max, and this is what I bumped into.

I had a Windows partition before I installed El Capitan, and now I can't boot into it.


Recovery/transformation command (? for help): v


No problems found. 271968965 free sectors (129.7 GiB) available in 2

segments, the largest of which is 271968959 (129.7 GiB) in size.


Recovery/transformation command (? for help): p

Disk /dev/disk0: 976773168 sectors, 465.8 GiB

Logical sector size: 512 bytes

Disk identifier (GUID): 6D5005D3-D6FA-41B3-B5C1-BF79AA91807C

Partition table holds up to 128 entries

First usable sector is 34, last usable sector is 976773134

Partitions will be aligned on 8-sector boundaries

Total free space is 271968965 sectors (129.7 GiB)


Number Start (sector) End (sector) Size Code Name

1 40 409639 200.0 MiB EF00 EFI System Partition

2 409640 703534639 335.3 GiB AF00 Macintosh HD

3 703534640 704804175 619.9 MiB AB00 Recovery HD


Recovery/transformation command (? for help): o


Disk size is 976773168 sectors (465.8 GiB)

MBR disk identifier: 0x4A414CA0

MBR partitions:


Number Boot Start Sector End Sector Status Code

1 1 976773167 primary 0xEE


Recovery/transformation command (? for help):

i'm literally right here with you. I've got the same exact output from gdisk and have been researching & trying everything i can find/think of to get the dualboot BOOTCAMP partition alongside el capitan.


windows 10 install DVD is repulsed by the partition scheme that bootcamp hands over...

I ran TestDisk in deep search mode, it took the whole day. It found bad sectors, and stated that

the partitions were un-recoverable. Unfortunately I lost the text that TestDisk produced when I pressed "continue"

in hopes of finding a recovery menu.


EDIT:

I decided to use a data recovery tool, and just clean reinstall everything. Apple has been disappointing lately.

If I post the output from my mac can you give me the correct commands to run?



drlaptop2:~ nick$ diskutil list

/dev/disk0 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *500.3 GB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_CoreStorage Macintosh HD 363.1 GB disk0s2

3: Apple_Boot Recovery HD 650.0 MB disk0s3

4: Microsoft Basic Data 40.0 GB disk0s4

/dev/disk1 (internal, virtual):

#: TYPE NAME SIZE IDENTIFIER

0: Apple_HFS Macintosh HD +362.7 GB disk1

Logical Volume on disk0s2

166585AC-7A6E-40C0-9974-779B2B18C707

Unencrypted

drlaptop2:~ nick$ diskutil cs list

CoreStorage logical volume groups (1 found)

|

+-- Logical Volume Group 4029CA8C-DEF1-483A-8E10-DC24653FCFE6

=========================================================

Name: Macintosh HD

Status: Online

Size: 363088445440 B (363.1 GB)

Free Space: 19005440 B (19.0 MB)

|

+-< Physical Volume 1123EC82-133F-4F4C-94C1-A87E7820CC68

| ----------------------------------------------------

| Index: 0

| Disk: disk0s2

| Status: Online

| Size: 363088445440 B (363.1 GB)

|

+-> Logical Volume Family C5972A27-BC02-4561-9436-54C6BA25970A

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

Encryption Type: None

|

+-> Logical Volume 166585AC-7A6E-40C0-9974-779B2B18C707

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

Disk: disk1

Status: Online

Size (Total): 362717118464 B (362.7 GB)

Revertible: Yes (no decryption required)

LV Name: Macintosh HD

Volume Name: Macintosh HD

Content Hint: Apple_HFS

drlaptop2:~ nick$ sudo gpt -vv -r show /dev/disk0

Password:

gpt show: /dev/disk0: mediasize=500277790720; sectorsize=512; blocks=977105060

gpt show: /dev/disk0: Suspicious MBR at sector 0

gpt show: /dev/disk0: Pri GPT at sector 1

gpt show: /dev/disk0: Sec GPT at sector 977105059

start size index contents

0 1 MBR

1 1 Pri GPT header

2 32 Pri GPT table

34 6

40 409600 1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B

409640 709157120 2 GPT part - 53746F72-6167-11AA-AA11-00306543ECAC

709566760 1269536 3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

710836296 188145592

898981888 78123008 4 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

977104896 131

977105027 32 Sec GPT table

977105059 1 Sec GPT header

drlaptop2:~ nick$ sudo fdsik /dev/disk0

sudo: fdsik: command not found

drlaptop2:~ nick$ sudo fdisk /dev/disk0

Disk: /dev/disk0 geometry: 60821/255/63 [977105060 sectors]

Signature: 0xAA55

Starting Ending

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

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

1: EE 1023 254 63 - 1023 254 63 [ 1 - 409639] <Unknown ID>

2: AC 1023 254 63 - 1023 254 63 [ 409640 - 709157120] <Unknown ID>

3: AB 1023 254 63 - 1023 254 63 [ 709566760 - 1269536] Darwin Boot

4: 0C 1023 254 63 - 1023 254 63 [ 898981888 - 78123008] Win95 FAT32L