Missing bootcamp option after upgrading to macOS 15.6.1

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Level 1

4 points

Missing bootcamp option after upgrading to macOS 15.6.1

I had bootcamp installed (first Win10 then Win11 bypassing the 'this computer doesn't support Win11') on my old Intel macmini 2018. Did a recent upgrade to 15.6.1 and while the bootcamp drive is there, I can't access Windows as a startup option holding the alt/option key. I do have a time machine backup done just before the upgrade so will restoring to that bring back the ability to access Windows bootcamp, or is there another fix other than re-installing Windows bootcamp?

The reinstall would involved the whole Win10 go to Win11, bypass computer not compatible with Win11, get the drivers for my old RX Vega 64 graphics card in the eGPU to work on Win11... which is possible but takes a long and somewhat frustrating time. Hoping there is a quicker solution to this. Thanks.

Mac mini, macOS 15.6

Posted on Aug 23, 2025 05:30 PM

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Answer 1

HWTech

Level 9

66,674 points

Aug 23, 2025 07:54 PM in response to simon314man

Time Machine only backs up macOS volumes. I don't think there is anything there that will affect the ability to boot Windows. Windows booting relies on the hidden EFI partition and the various Microsoft Windows partitions. Any change to the partitions would definitely prevent Windows from booting.

I think you will need to reinstall Windows to fix the Windows boot issue. That may require using Bootcamp Assistant to remove the Windows installation, then start the Windows Bootcamp installation again. Back in the Windows 7 days, it was possible to boot the Windows installer into special mode where you could try using an automated boot repair fix, but that is not easy to access with Win10+ and I don't even know if it would even work on a Mac.

You can try making a bootable rEFInd USB stick to see if rEFInd can boot your broken Windows install. If so, then you can install rEFInd to the internal SSD to use as the default Startup Disk. Even when you install rEFInd to the internal SSD it does not make any changes to macOS or Windows....it places special boot files onto the hidden EFI partition which is only accessed when using Startup Disk System Settings or when Option Booting the Mac.

FYI, Apple does not support Windows 11 so you were running an unsupported configuration. This is one of the risks of unsupported configurations. Even with a support configuration, dual booting is always at risk of having issues since Windows doesn't understand the concept of dual booting....even when dual booting two versions of Windows. It is great when it works, but when something goes wrong you are in for some pain & work to resolve it.

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Answer 2

simon314man Author

Level 1

4 points

Aug 24, 2025 04:29 PM in response to HWTech

Thanks, yeah I had to go to Win11 to get a version that worked with my eGPU and my old RX Vega 64 card. I couldn’t get any version of Win10 to work. Oh well, time to put aside a day to redo bootcamp.

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