Q: How can I repair my Windows Bootcamp?
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Jun 12, 2015 8:35 PMby Loner T,Install GPT Fdisk (aka gdisk).
Leave your Testdisk display and start a new Terminal Window. 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 Testdisk output (and you can verify) in Steps 7 and 8. Please notice the '+' sign in step 8. The text in parentheses is for informational purpose to describe the action being taken. Gdisk has one-character commands.
Rebuild GPT4 using start/end offsets
- Sudo gdisk /dev/rdisk0
- P (print the full list of parts)
- D (delete)
- 4 (part 4)
- N (new part)
- 4 (part 4)
- 667831308 - Start offset in bytes (start point for Bootcamp part)
- +313882617 - Size offset (as opposed to End offset)
- 0700 (Windows part type)
- P (print list of all parts just to see what changes will be made)
- W (Write the new GPT)
- Y (Yes! really write the new GPT)
This will delete and re-write the GPT partition info for /dev/disk0s4.
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.
- Sudo gdisk /dev/rdisk0
- P (Print list of parts)
- R (Recover)
- O (print current Hybrid MBR)
- H (chooses Hybrid)
- Partitions numbers to be hybridized: 2 3 4
- Y (Good for GRUB question)
- N (part 2 boot flag)
- N (part 3 boot flag)
- Y (part 4 boot flag make NTFS bootable partition)
- O (print current Hybrid MBR)
- W (Write the new MBR)
- Y (Yes! write the new MBR)
- 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
Test 1 - Does Bootcamp Volume show up in Finder?
Test 2 - Can you see files in Bootcamp Volume?
Test 3 - Can you select Bootcamp in System Preferences -> Startup Disk?
Test 4 - If Test 3 is successful, select Bootcamp and Click Restart.
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Jun 13, 2015 10:04 PMby Loner T,You have a typo in step 7 in the first set of Gdisk steps. You are using 667831304, but step 7 shows 667831308 as the value to be used. The 4 sector difference at the beginning of the partition is crucial.
Can you repeat both sets of Gdisk steps and test again? In the second of Gdisk steps, you have typed an 'n' for a MBR hex code which shows up in MBR2 as Xenix /usr partition, but it should be Apple HFS/HFS+.
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Jun 14, 2015 5:24 AMby Loner T,Yes, it does. Please see how to set it to 1-sector alignment as shown. Once you set it to 1-sector boundary, continue the same session with Step 2 of the first set of Gdisk steps (do not exit from Gdisk).
sudo gdisk /dev/disk0
GPT fdisk (gdisk) version 1.0.0
Warning: Devices opened with shared lock will not have their
partition table automatically reloaded!
Partition table scan:
MBR: hybrid
BSD: not present
APM: not present
GPT: present
Found valid GPT with hybrid MBR; using GPT.
Command (? for help): x
Expert command (? for help): d
Partitions will begin on 8-sector boundaries.
Expert command (? for help): l
Enter the sector alignment value (1-65536, default = 2048): 1
Expert command (? for help): d
Partitions will begin on 1-sector boundaries.
Expert command (? for help): m
Command (? for help):
