Boot Camp partition not mounting

I can no longer boot into my Windows 7 Boot Camp partition. I had created a third partition for installing Mountain Lion to test some old software so maybe that's the reason? How do I get back into Win7 Boot Camp?


MacBook Air 13", macOS 10.14

Posted on Dec 13, 2019 10:21 AM

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Posted on Dec 17, 2019 10:39 AM

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. Please see the sample Q&A before you execute these steps.


  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: 2 3
  7. Y (Good for GRUB question)
  8. N (part 2 boot flag)
  9. Y (part 3 boot flag make NTFS bootable partition)
  10. O (print current Hybrid MBR)
  11. W (Write the new MBR)
  12. Y (Yes! write the new MBR)
  13. 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 07): Press Enter/Return
Set the bootable flag? (Y/N): Y


If you are asked about additional space, say 'N' and continue.


105 replies
Question marked as Top-ranking reply

Dec 17, 2019 10:39 AM in response to ckahn

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. Please see the sample Q&A before you execute these steps.


  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: 2 3
  7. Y (Good for GRUB question)
  8. N (part 2 boot flag)
  9. Y (part 3 boot flag make NTFS bootable partition)
  10. O (print current Hybrid MBR)
  11. W (Write the new MBR)
  12. Y (Yes! write the new MBR)
  13. 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 07): Press Enter/Return
Set the bootable flag? (Y/N): Y


If you are asked about additional space, say 'N' and continue.


Dec 22, 2019 10:16 AM in response to Loner T

According to the Boot Camp support page, Mojave Boot Camp Assistant will only let you install Win10. But shouldn't a Winclone restore bypass the Mojave Boot Camp objection? Are the drivers that come with W7 enough to get it to boot into a MBP2018 and then do the upgrade to Win10 there? The Boot Camp drivers are for unique hardware features of the Mac, no? Such as brightness control, and now touchbar. So if those drivers were not present I could still use the keyboard, mouse and basic gpu functionality to get a Win10 install started. I just don't understand why the Wincloned partition didn't boot on the MBP2018. I'll restore it again and see what happens.

Dec 22, 2019 3:28 PM in response to ckahn

ckahn wrote:

According to the Boot Camp support page, Mojave Boot Camp Assistant will only let you install Win10. But shouldn't a Winclone restore bypass the Mojave Boot Camp objection?

Are you aware of this restriction - http://twocanoes.com/winclone-image-compatibility-with-512-and-4k-block/ ?

Are the drivers that come with W7 enough to get it to boot into a MBP2018 and then do the upgrade to Win10 there?

No.

The Boot Camp drivers are for unique hardware features of the Mac, no? Such as brightness control, and now touchbar.

Yes.


So if those drivers were not present I could still use the keyboard, mouse and basic gpu functionality to get a Win10 install started.

On which Mac - 2013 or 2018? W10 installation on either Mac will work, if you use BCA which downloads the appropriate drivers.

I just don't understand why the Wincloned partition didn't boot on the MBP2018. I'll restore it again and see what happens.

See the WinClone link for details. You should ask the TwoCanoes if they can specifically address the link that I posted.

Dec 27, 2019 9:04 AM in response to ckahn

It should take 5 minutes or less, if this was working properly.


Do you have a Time Machine backup? If yes, then my recommendation is - (on the 2013 MBA)


  • Boot into Internet Recovery
  • Erase your internal disk
  • Restore your TM backup
  • Restore your W7 Winclone backup to a much larger partition than originally used by W7
  • Upgrade to W10
  • Test and verify
  • Now you can Winclone W10 (upgraded from W7)
  • Run SysPrep and create a new W10 Winclone image
  • Try to Restore this SysPrep'd W10 to 2018 Mac
  • Test



Dec 27, 2019 7:24 PM in response to ckahn

Are you trying this on the 2013 MBA or 2018 MBP?


2013 MBA should support a USB2 Flash drive formatted as MBR/FAT for W7. For W10, you can use a PC and Windows Media Creation Tool to create a bootable USB, but you will need to add BC drivers for it to work.


2018 MBP has secure boot, so you will need to look at the settings. See About Secure Boot - Apple Support for reference.

Dec 28, 2019 8:29 PM in response to ckahn

ckahn wrote:

Tim Perfitt, founder of Two Canoes Software, wrote: "I usually do my migrations without sysprep. If I am having boot issues that are blue screen / boot related and I can’t get to the desktop is what I turn to sysprep. Haven’t had to do that in a while."

SysPrep generalizes Windows by removing any hardware-specific information from Windows. It uses the installed drivers' INF files to do so. Running a SysPrep on 2018 makes no sense. He is contradicting his own KB article.

Booting isn't an issue now. Boot Camp driver installation is the issue now.

Yes, and it will be because Registry entries are no longer valid on the 2018 Mac.

Not having any other ideas, I thought I'd give SysPrep a try at this late stage, hoping it would reset any driver issues, if driver issues are what is preventing Boot Camp driver installation from completing its task.

Microsoft's article clearly states that the generalized images are pushed to new devices, which do not have the same hardware as the source installation. Take a look at "Prevent Sysprep from removing installed devices" part. I use SysPrep to remove all hardware specific information on the source (Dell) to migrate to destination (HP/Asus/Lenovo) devices.


I've been following this document of instructions:

https://twocanoes.com/knowledge-base/migrating-windows-10-to-a-16-macbook-pro-2019-with-winclone-8/

Even though I have a MBP2018 13", not a MBP2019 16". The Touch Bar makes the instructions seem relevant to my situation and there is no page for MBP2018. The trouble with a lot of the Two Canoes documentation is that the details refer to interfaces that are no longer in the current OS or the current Winclone, such as the "how to partition" instructions, which has changed a lot in MacOS.

You may want to ask Tim for clarifications.

The last instruction is to run the setup.exe Boot Camp executable. The page doesn't go beyond that.

Can you post the PID/VID of the NCM entries? I will assume that you are using BC drivers package that came from BC Assistant -> Action -> Download on the 2018 MBP.



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Boot Camp partition not mounting

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