So I took the offer to upgrade from Workstation. Ran the wizard with all the defaults. The only thing I didn't check (I usually do) was the enhanced Keyboard driver (that requires restart). The upgrade went through successfully. I even used some VMs.
Then I had to restart my host and when it came back, behold, keyboard and mouse were unusable).
I tried connecting an external usb keyboard; didn't work.
An external mouse did work.
After I removed 15.5.1-15018445 and restarted, I was able to re-gain keyboard use. Anyone else experiencing something similar?