回答“macOS Sierra won't boot (bootcamp win10)”Not sure if it's relevant to your problem, but I had a similar experience. I updated to High Sierra then Windows 8.1 was no longer not willing to boot. It starts with the blue Windows logo, tries to load, then fails with a BSOD. I tried reinstalling Windows 8.1 from scratch by deleting the Boot Camp partition, creating it again, and installing Windows. After Apple's Boot Camp's software install (in the running Windows) and rebooting, it BSOD'd again. I read around that apple was putting APFS on High Sierra, but not if you have a Fusion Drive (this is my case). To me it means that reading HFS+ or APFS files caused a problem. So I did it again (delete partition, create partition, install Win, install Apple Boot Camp's software). Then, without rebooting, I removed the HFS+ Driver from Windows using the instructions at the bottom of http://lpmv.epfl.ch/page-109141-en.html How to Remove Apple HFS+ Driver: (1) Browse to C:\Windows\System32\drivers (2) Rename AppleHFS.sys & AppleMNT.sys to AppleHFS.sy_ &...