From OpenZFS on OS X
Windows Boot Crashes
If you find that ZFSin is crashing everytime you boot Windows, you can remove the kernel extension part.
- When booting, once you get to the spinning dots part - turn off your PC - either by holding power button for 10s, or cutting power.
- Doing that 2 times in a row, Windows will ask if you have boot issues.
- Enter Troubleshoot, Advanced Options, then Command Prompt.
- Navigate to your hard disk, which might not be C: during boot command console. Change drive letter, and issue "dir" until you recognise your disk.
- cd into Windows\System32\Drivers
- dele ZFSin.sys
- exit command prompt
- use menus to boot normally.