Select your device and then scroll down until you see an option for Sync Now. As soon as you tap on this option, your Fitbit ...

3. Disconnect the Fitbit One from its power source and wait a moment, then depress its button until the unit turns on. The tracker has now been restarted and should work properly again.

Try to determine where your phone was at the time of the last sync, and concentrate your search there. Take the phone that you've paired with your Fitbit and bring it to where you might have last ...