I was having the same problem.Make sure you have ver 2.60 you can check this by having the unit off,then press and hold the center joystick and turn it back on.at the top it should say 2.60.if it doesnt give garmin a call.make sure you have your usb and by your pc next to you.their service is a+++++
waas enabled
gs84
off road
this thing is so accurate i almost trip on caches.it even shows elevation difference between floors IN MY HOUSE.Im located 35mi west of chicago.
Good luck!
Banderlog