The Lighting Controller

I bought a new fog machine. I cannot remove the old fixture. After REMOVE old fixture, this old fixture appears at the same dmx adress in FIXTURES. While add new fixture, software shut down.
What is a problem?

Please post a link of a ZIP of your lightshow (https://thelightingcontroller.com/viewt ... ?f=3&t=168), and tell exactely what action to do to get the problem.
And we will check that.