System does not crash in safe mode.. however teamviewer just did. /sigh
My brother started up teamviewer for me.

elevated command prompt in safe mode
dism /online /cleanup-image /restorehealth
...

I'm using Windows 10 as a host for a Hyper V guest for Ubuntu 14.04
I changed the bootloader on the Linux guest and rebooted. It wouldn't come back up.
So I attempted to attach the Ubuntu ISO and...