Recently set up a new computer and for some reason, my Nashville kits aren’t loading in Groove Agent 4 64bit but DO work in Groove Agent SE. I’ve tried reinstalling both the Nashville kits and Groove Agent 4 but neither has worked.
Were you able to solve? I am having similar issue with two newly bought expansion instruments (Metro Heights and Neuro Mindset.) They load in GA SE, but not in GA4. Other expansion instruments I just bought load in both no problem.
Steinberg is so “intelligent” to hand out a stone old installer for GA4. Check if you have the latest updates. I had this problem with another Expansion as I stupidly thought that a brand new absolute download would contain the current installer, but alas…