Error message "There is data for an unknown fixture ..."

[support]

At scene load, Steps pops up this message when it reads data for a fixture which is not anymore in the tab "Fixtures". Please keep in mind that V8 is fixtures based programming, this means the software is not able to generate the channels data for a non existing fixture.

If you can replace the missing fixture as it was in the tab "Fixtures", before the scene has been saved, this will fix the problem.
If you can not replace the fixture, then you have no choice to re-save the scene, and the data for the lost fixture will be lost to.