ColorCorrect - causes RGBA channels to look like tiny dots

It's been 6 months since I used Fusion - was new to it then.

I've loaded a half float exr, plugged it into a CC node and for some reason, if I adjust colours, levels on anything apart from Master it stuffs up my image.

Attached demonstrates the issue.

Also I'm using the paid version - do I need to do anything special to get it to read the dongle? There are a few options that I click and it says I need the studio version.

Turns out that I had installed the free version at some point. The Studio version doesn't have the same problem.

The free version shouldn't have done that, either. I haven't seen anything like that before. I'm curious what the error message in your Console was. I suspect it was probably something about an OCL kernel. I'll bet if you turned off OpenCL for that node the problem would have gone away.

I would also posit that you were still running 9.0 initially, which had some bugs in the OpenCL for CC and Gamut, and possibly some other color-related nodes.

I'm pretty sure the console said that I needed to buy a Studio license - but not 100% on that.

Is there a guide anywhere that would help me to set Fusion up to get the best out of my hardware?