What should you do first if an application on your mobile device has crashed and is unresponsive?

Any unresponsive app on your mobile device should be force-closed first. Depending on whether it's an Apple or an Android device, the process will vary. Try restarting your device if the app is still causing problems. If that doesn't work, uninstall and reinstall the app. It shouldn't be necessary to revert your mobile device to factory defaults.