I was having the same trouble lately, and soft reset was not working. Reloading unit with caches from GSAK did nothing. I updated the firmware, went caching, and at some point in my caching today, I tried to calibrate. Still no luck. Came home today, reloaded the same firmware, disconnected from the computer, went outside right away (before doing anything else with unit), and that worked. I was finally able to calibrate.