I just finished my China trip... Catymag is right. I switched on the gps and held it by the window side in my hotel room for about 3-5 mins, it acquired satellite eventually!! My Garmin worked just fine for the entire trip. I even used it to monitor the speed of the new bullet train in China! (See attached photo that I have taken)
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However, when it comes to direction navigation (pedestrian mode), I'm a bit disappointed because some of the directions it showed me were inaccurate. I had to ask the local or look for sign post to walk differently from what was shown on Garmin to reach my destination. Could it be because I have not installed the latest China map??