Uninstall Garmin Express from the Control Panel if Garmin Express Not Working. In the control panel, you will have to navigate to devices and networks. Uninstall the Garmin Express program by selecting the re-install or uninstall option. After you've completed this, head to the Garmin Express download page. Download the whole Garmin Express setup file and reinstall the program. Unless there is an issue with the driver files, the Garmin Express should now function correctly.