Can't boot back into OS X. Partition appears to still be there, but does not show up on PC

Hello everyone,


I've been searching all over the place for fixes of this problem, but I can't seem to find anything that will work.


Yesterday I decided to set up Boot Camp again after I lost it when my computer needed repairs last year. I installed Windows 7 through Boot Camp with no complications (other than the partition initially failing to be created, which I was able to solve) and then upgraded to Windows 10. Everything seemed to be running as expected, but when I went to boot into OS X from the Boot Camp icon in the system tray, my computer simply restarted back into Windows. When I restarted to computer again and pressed alt/option to bring up the startup disks, only the Windows disk showed.


So, I booted my computer into Recovery mode (Internet Recovery mode started up--I read on Apple's site, that this would happen if no OS is installed?) and checked Disk Utility to make sure I hadn't lost all of my files. My Mac partition still seemed to be there and with all files intact. I repaired the disk just to be safe, exited out of Recovery mode and selected OS X as the startup disk, but it still started right back up into Windows. At this point I figured maybe something had happened to OS X or it had gotten deleted somehow, so I went back into Internet Recovery and tried to reinstall OS X, but was unable to (I believe it said the disk couldn't be verified, but I can't remember for sure).


But now the part that has me baffled the most. I ran diskutil list in Terminal, and it listed 13 disks, with Macintosh HD as the last one. Most of the disks were small, only a few megabytes or so, but I have no idea where they came from or what they are.


I'm at a complete loss at this point. Any help is greatly appreciated.

Thank you.

MacBook Pro (13-inch Mid 2012), OS X El Capitan (10.11.1)

Posted on Nov 7, 2015 4:44 PM

Reply
34 replies

Nov 7, 2015 5:18 PM in response to mtaylor1326

1. Your Windows installation seems to have corrupted your GPT.

2. In Recovery, (your Local Recovery is corrupted/mislabeled) so you are in Internet Recovery and booted from Apple servers. The small disks are parts of images provided by Apple servers.

3. Please boot into Windows and download GPT Fdisk from http://sourceforge.net/projects/gptfdisk/ .

4. Once GPT Fdisk is installed, you can run it from a Windows CMD window with Admin rights and post the output of the following command set.

gdisk64.exe 0:

p

q

User uploaded file

Nov 7, 2015 6:33 PM in response to mtaylor1326

Can you post the output similar to the following?


Command (? for help): r


Recovery/transformation command (? for help): o


Disk size is 500118192 sectors (238.5 GiB)

MBR disk identifier: 0xAE6E4269

MBR partitions:


Number Boot Start Sector End Sector Status Code

1 1 409639 primary 0xEE

2 409640 250801735 primary 0xAC

3 250801736 252071271 primary 0xAB

4 * 252071936 500117503 primary 0x0C


Recovery/transformation command (? for help): m


Command (? for help):

Nov 7, 2015 6:42 PM in response to Loner T

Okay, does this work better?


Partition table scan:

MBR: hybrid

BSD: not present

APM: not present

GPT: present


Found valid GPT with hybrid MBR; using GPT.


Command (? for help): p

Disk 0:: 976773168 sectors, 465.8 GiB

Logical sector size: 512 bytes

Disk identifier (GUID): 6DD42B66-E9AE-4F3C-AC65-3FD2EC9B1FF1

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 1773 sectors (886.5 KiB)


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

1 40 409639 200.0 MiB EF00 EFI System Partition

2 409640 584878599 278.7 GiB AF05 Macintosh HD

3 584878600 586148135 619.9 MiB AB00 Boot OS X

4 586149888 976773119 186.3 GiB 0700 BOOTCAMP

Nov 7, 2015 6:56 PM in response to mtaylor1326

The r and o sequence will show if you have a Hybrid MBR. Do not use the o command on the main menu. Your GPT looks correct.


Can you 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


and test booting into OS X using Alt/Option key?


Also, if you have Control Panel -> System -> Boot Camp, you can select OS X from it and reboot into OS X. This requires that you have Bootcamp drivers already installed and working.


Please also see Boot Camp: Set the default operating system .

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Can't boot back into OS X. Partition appears to still be there, but does not show up on PC

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