Interesting. I bought a brand new Windows Arm machine the other day that was DOA: It booted with the UNMOUNTABLE_BOOT_VOLUME message. I brought it back to Microcenter and exchanged it and the replacement works fine. I wonder if that machine was just updated at the factory before it shipped...

I'm a longtime Microsoft fanboy, but even I wait a couple of weeks before updating anything, unless there's an actual problem I need the fix for.