Boot Camp Partition not mounting

From Boot Camp 5.1: Frequently asked questions - Apple Support

Can I resize the Windows partition after installing Windows?

No. Back up your important files, then use Boot Camp Assistant to delete the old partition and create a new one.

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.

If you notice there is large gap between GPT 3 and GPT4 and your MBR is out of sync with the GPT. OSX reads the GPT, not the MBR, Windows is reversed.

If Windows is currently working as expected, please download GPT Fdisk - http://sourceforge.net/projects/gptfdisk/ and install it. You need to use the following steps.

If you see any error messages during the following steps, please stop and post back here with the error message. The following steps have values from your MBR output (and you can verify) in Steps 7 and 8. Your MBR is the source for these two values. Please notice the '+' sign in step 8. The text in parentheses is for informational purposes and is not entered. Most commands in Gdisk are one-character only and values are numeric with the '+' sign, if necessary.

Rebuild GPT4 using start/end offsets

1. Sudo gdisk /dev/rdisk0
2. P (print the full list of parts)
3. D (delete)
4. 4 (part 4)
5. N (new part)
6. 4 (part 4)
7. 1760004096 - Start offset in bytes (start point for Bootcamp part)
8. +193519616 - Size offset (as opposed to End offset)
9. 0700 (Windows part type)
10. P (print list of all parts just to see what changes will be made)
11. W (Write the new GPT)
12. Y (Yes! really write the new GPT)

This will delete and re-write the GPT partition info for /dev/disk0s4.

Reboot and test.

Excellent. Please take new back ups of OSX and Windows to separate external disks and use for future recovery.

Your MBR is no longer valid, due to the addition of the Transfer partition. Do you need the Gdisk steps to re-create the MBR. Since you now have 5 GPT entries, you will lose visibility to OSX partition from the Windows side.

This is not a standard Hybrid MBR. Standard MBR contains GPT 2,3,4 but we are using GPT3,4,5.

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 thesample 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.

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: 3 4 5
7. Y (Good for GRUB question)
8. N (part 3 boot flag)
9. N (part 4 boot flag)
10. Y (part 5 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 #3 (MBR partition #2)

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 #3)

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

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

Creating entry for GPT partition #5 (MBR partition #4)

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

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

Please post the output of the GPT and Fdisk commands.

Hi Loner T.. thanks for supporting this thread -I feel like I've almost got my fix for nearly the same problem.

Just updated a Mid2007 MacbookPro (intel dual core, 4GB RAM, etc.) to Yosemite. I can start Windows 7 (bootcamp install) by using (Command) on start-up, but can't select the start-up disk from system preferences. The icons are there, but grayed out.

I've followed your instructions up to this point, but don't want believe the Gdisk Steps are the same.

Last login: Fri Oct 23 15:13:01 on console

Michael-Marquezs-MacBook-Pro:~ michaelpmarquez$ diskutil list

/dev/disk0 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *250.1 GB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_HFS Macintosh HD 133.5 GB disk0s2

3: Apple_Boot Recovery HD 650.0 MB disk0s3

4: Microsoft Basic Data BOOTCAMP 115.7 GB disk0s4

Michael-Marquezs-MacBook-Pro:~ michaelpmarquez$ diskutil cs list

No CoreStorage logical volume groups found

Michael-Marquezs-MacBook-Pro:~ michaelpmarquez$ sudo gpt -vv -r show /dev/disk0

We trust you have received the usual lecture from the local System

Administrator. It usually boils down to these three things:

#1) Respect the privacy of others.

#2) Think before you type.

#3) With great power comes great responsibility.

Password:

gpt show: /dev/disk0: mediasize=250059350016; sectorsize=512; blocks=488397168

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 488397167

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 260712632 2 GPT part - 48465300-0000-11AA-AA11-00306543ECAC

261122272 1269536 3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

262391808 226004992 4 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

488396800 335

488397135 32 Sec GPT table

488397167 1 Sec GPT header

Michael-Marquezs-MacBook-Pro:~ michaelpmarquez$ sudo fdisk /dev/disk0

Disk: /dev/disk0 geometry: 30401/255/63 [488397168 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: AF 1023 254 63 - 1023 254 63 [ 409640 - 260712632] HFS+

3: AB 1023 254 63 - 1023 254 63 [ 261122272 - 1269536] Darwin Boot

*4: 07 1023 254 63 - 1023 254 63 [ 262391808 - 226004992] HPFS/QNX/AUX

Please help.

Thanks in advance,

Michael

You are running El Capitan, not Yosemite. Please click on the lock, enter your password when prompted, and then select Bootcamp and Restart.

Ha! So many hours wasted... you're a genius. (and I'm numb from 3 failed El Capitan installs and 2 bootcamp installs)

Can't thank you enough...

Regards,

Michael

Lowkeythunda wrote:

Ha! So many hours wasted... you're a genius. (and I'm numb from 3 failed El Capitan installs and 2 bootcamp installs)

I would blame it on the 2 Windows installs. 😁😝. Glad to see it working.