Unable to convert "normal" project to this mongame fork.

[pjorus720-cmd]

Yello!
I have been trying for longer then I want to admit to get compute shaders to work in the Monogame compute shader fork, but i think i have a (mostly) working setup now.
However when I create a .fx file in the content manager, make a reference to it in my code and run the game I get the following error:
Unhandled exception. System.Exception: This MGFX effect is for an older release of MonoGame and needs to be rebuilt.
Also my content editor is unusable for some reason (see image).
Any help would be greaty appreciated!