BootCamp partition suddenly not available as a boot option in MacOS Big Sur

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Level 1

23 points

BootCamp partition suddenly not available as a boot option in MacOS Big Sur

Full issue description:

A couple of days ago I was able to boot into windows via bootcamp without any issues. A few days later suddenly I was unable to see the windows boot partition on the boot selection screen.

I previously had paragon NTFS filesystem support installed and thereby was unable to select Boot Camp as the default boot partition in Startup Disk because it was mounting to drive and read and write mode. I have since uninstalled paragon software selected BootCamp as the default boot partition but during boot I get an infinite spinning circle (see image, this isn’t the Windows boot dots) until it defaults to MacOS.

This is happened to me twice now once during the beta and once in the full release. During the beta the only solution that I could find was to reinstall Boot Camp from scratch. This time I’m determined to find a solution to get the Boot Camp partition to appear at boot so I can select it and boot from it.

Any thoughts?

MacBook Pro

Posted on Dec 5, 2020 2:00 PM

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Answer 1

Top-ranking reply

Loner T

Level 9

59,536 points

Dec 5, 2020 8:59 PM in response to z3thon

z3thon wrote:

I previously had paragon NTFS filesystem support installed and thereby was unable to select Boot Camp as the default boot partition in Startup Disk because it was mounting to drive and read and write mode.

There is a race between the Paragon driver and the Apple driver. This can cause much pain and grief.

I have since uninstalled paragon software selected BootCamp as the default boot partition but during boot I get an infinite spinning circle (see image, this isn’t the Windows boot dots) until it defaults to MacOS.

Windows will not boot, if the NTFS file system is dirty and cannot be corrected. Paragon can leave the file system dirty. This has been an ongoing issue for many years.

This is happened to me twice now once during the beta and once in the full release. During the beta the only solution that I could find was to reinstall Boot Camp from scratch. This time I’m determined to find a solution to get the Boot Camp partition to appear at boot so I can select it and boot from it.

If you are still running into issues, you may need to boot from an external Windows installer and manually run chkdsk.

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Answer 2

Dec 7, 2020 10:08 AM in response to z3thon

FWIW, I had that happen with the transition to Catalina and was clear that Paragon was the culprit. Did a clean install without Paragon and all was good; fully selectable startup drive.

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Answer 3

z3thon Author

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23 points

Dec 5, 2020 2:19 PM in response to z3thon

Does anyone know how to check whether your Boot Camp partition is in an EFI/Legacy boot format? Is it possible that Paragon's software changed my drive from an EFI to a Legacy BIOS boot and is thereby unsupported somehow? I am on a 2020 MBP 13"

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Answer 4

Dec 7, 2020 9:19 AM in response to Loner T

Can anyone say that Big Sur does support Bootcamp? I have a clean install with no Paragon involvement, but don't want to go down this path if Big Sur simply won't support Bootcamp without a complete repartition and reinstall of Windows.

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Answer 5

z3thon Author

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23 points

Dec 7, 2020 9:54 AM in response to walterfromhouston

Yes. But as I said. This is the second time this issue has happened while I’ve been using Big Sur. I don’t know if it’s correlated to Big Sur but my ability to select my BootCamp at startup suddenly disappeared. On both occasions I didn’t do anything different than I have in the past. It just suddenly wasn’t a selectable bootable entity.

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Answer 6

Dec 7, 2020 9:34 AM in response to z3thon

Now that you have, does it work properly? Can you specify Bootcamp as the startup disk via System Prefs?

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Answer 7

Loner T

Level 9

59,536 points

Dec 5, 2020 9:01 PM in response to z3thon

z3thon wrote:

Does anyone know how to check whether your Boot Camp partition is in an EFI/Legacy boot format? Is it possible that Paragon's software changed my drive from an EFI to a Legacy BIOS boot and is thereby unsupported somehow? I am on a 2020 MBP 13"

Paragon should not be changing your installation from UEFI to BIOS or vice-a-versa. A BIOS mode Windows requires a Hybrid MBR (or a MBR). Run

sudo fdisk /dev/disk0

and post the output. It is unlikely that you will see an MBR.

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Answer 8

z3thon Author

Level 1

23 points

Dec 7, 2020 9:35 AM in response to walterfromhouston

Boot Camp is supported. I'm just having a weird issue where the OS most likely somehow corrupts itself and then can no longer be recognized as a bootable device. I've never had this issue on any of the other releases, but it's hard to say that it's Big Sur's fault. In reality I probably should have booted into target disk mode and taken a look at the drive using another Windows computer that could check the disk for errors since macOS can't repair Windows NTFS partitions.

I ended up reinstalling cause I needed to use Windows at work on Monday (today).

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Answer 9

z3thon Author

Level 1

23 points

Dec 7, 2020 9:32 AM in response to Loner T

I ended up doing a fresh reinstall.

Trying to solve the issue was eating up too much time and I needed to be ready to work on Monday.

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BootCamp partition suddenly not available as a boot option in MacOS Big Sur

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