@ich777 recommended I open a bug report based on our conversation here      Please see diagnostics attached. If the dev team has time to look at it I'd be very grateful.   Basically, going from 6.9.2 -> 6.10rc2 gives me a code43 on my primary GPU passthrough for any new or previously existing Win10 VM and any new Win11 VM.   I've tried everything I can think of (see thread above) and nothing seems to fix the issue. I've rolled back to 6.9.2 in the meantime,