Booting a VM and you get the error “Failed to power on with Error ‘Incorrect Function'”? Yeah, this hit us too. Looks like it hits VMs with secure boot enabled.

Quick fix: Move, delete or rename the .mrt & .rct files associated with the .vhdx file that the OS of the non-booting VM normally boots from. It’ll then boot normally.

Alternatively you can uninstall the updates kb5031364 and/or kb5031361.