Thanks Nick! This has been driving me crazy for months. I would make sure the bluetooth was active on my watch, then open GC on my iPhone 6S - and wait. I would swipe down in GC, which would initiate the blue buffering icon, which I thought was telling it to update, but that basically never worked. I've only tried this once, but it worked like a charm. I hope this works, as I like to check in during the day to see where I am with the steps challenge, but can never get GC to sync. I just had to wait and every once in a while, seemingly at random, GC would actually sync. My new mantra "Open GCM, double press home, open any other app, then double press home again, choose GCM and a sync seems to get triggered".