Steve sometimes it will not finish if the Main controler is to warm. Sometime when I try, I get that stupid message and just click on it and proceed. All usually goes well unless I have been doing updates and calibrations then try the IMU it runs aroun but won't finish until I cool it down. I have to start the IMU cal fresh. Give it s try, may or may not work for you but I have done this seven times so now I touch the top of the quad and if it's warm to touch I let her cool down so I can get a good Calibration. Be sure to level your quad front to back and left to right.