Hi. There are a few things to check.
1) The external control menu - is this set to Serato DJ? You can see a section on External Control in the manual, here: https://www.inklen.com/mixemergency/manual/mainwindow/
2) Check that the upfaders, on the Control Window, are both up.
3) Check that no effects are applies to the left, right, and output channels.
4) Check that no overlays are enabled that might be covering the output.
5) Restart you computer.
If none of these help, then before launching MixEmergency, try renaming your MixEmergency folder to something else, like "MixEmergency Moved". You can find this folder in your Movies folder. This will reset a lot of the settings of MixEmergency (though, not all).
Let me know how you get on.
