New Mavic Air, prompted me out of the box to calibrate the vision system using DJI Assistant 2.  In the calibration screen of DJI Assistant 2, on the thrid page of the tutorial, the "Calibrate Now" button is greyed out, and a message says "Please reboot aircraft".  I can't move beyond that message. Rebooting the aircraft, changing batteries, reinstalling DJI Assistant, refreshing the firmware, all tried, but still prompts to reboot aircraft.  

I was able to reinstall DJI Assistant in Windows 10 with disabled driver signature enforcement, which allowed the vision calibration feature to work.