Mine does that to me at times too. 2 things I try to get it to acquire satellites - First I perform a master reset, Then I don't move the vehicle for 20 minutes so it can lock in on the satellites. It's worked for me.
This site shows all the master resets for the entire line of Garmins.
I hope that resolves your problem, as I did have a Tom Tom that had problems locking in on cold days. I had to let that one warm up before it started locking in on satellites.