Try resetting the Tracker. Place it on the base station, then press the button on the bottom of the base station using a toothpick, pen tip, or paper clip.

If your Tracker still does not sync, unplug your base station then uninstall and reinstall the software by going to www.fitbit.com/start. Once the installation is complete, plug-in the base station.

If you are using a Windows PC, there should be a Fitbit icon on the lower right corner of your computer screen, in your system tray. It should appear when the computer communicates with your base station and your unit. If it is blue and gray, this means that your base station is working. If the color of the icon is red and gray, please unplug the base station and plug it back in.