The adjustment brush is not responding at all (using any effect and yes, I have maxed it to 100 and -100) for me. It also won't show selected mask overlay. This has been true in Lightroom 5.7 on my old mac. I thought it would magically work if I upgraded so I downloaded the free trial of the latest Lightroom CC and on my new MacBook pro no less. There is no change though. The brush still won't work. Additionaly suggestions?
Please reset Lightroom CC 2015 preferences back to default and check if that helps.
Also, can share the screenshot for the problem.
Thank you dj_paige and @Mohit. Sounds a bit scary. I'll have to look into that when I have a bit more time. I'm not sure I'd know how to fix if if I lose something though my computer is backed up to time capsule.