On Windows, open Task Manager and confirm that the following processes are running: enfDispatcher.exe and enfeye.exe.
On Mac OS X and Linux, execute the following command line:
ps ax | grep enf
Confirm that the following processes are running: enfdispatcher and enfeye.bin.
If the enfeye process is not running, reboot the machine.
If the enfdispatcher process is not running, check out the enfdispatcher section.