Also a side note in Case this is partially a CPU issue, I'm using an AMD Ryzen 9 5950X 16-Core Processor
Still having issues, even after the workaround of merging skinned character parts - which becomes a weight painting issue later. Anyway, I had been creating some morphs and updated them in CC then closed CC for the night but the next day, I opened the project up and tried sending a new morph to facial profile editor and it tells me I have to choose GoZ All -which I did. I even tried making a fresh Zbrush project and cleared the GoZ Plus Cache, Zbrush was able to load the character but sending the morph back the same message "choose GoZ All" again happened.
Update: Thankfully Rampa helped out with a workaround which was to merge non body parts. Later I identified a trouble making mesh specifically which was "hose07" I discovered that hose07 didn't want to merge with the other hoses or else CC4 would crash. I also tried merging hose07 with the hose connector, that worked until I tried merging the other hoses with the same connector -very odd. This could of been the reason why it didn't send over to Zbrush until hose07 was merged inside another part. I didn't have to merge all non body parts to get it working again, the issue only seems to be related to hose07. This is still worth investigating because there shouldn't have been be any issue and I don't know what problems I may have in the future continuing to work on the character - it would be a very painful CC4 experience if I had to for some reason start all over creating the character. It wouldn't be much of an issue/work around if I could simply swap out the hose but AccuRig doesn't allow existing weight painted systems to be imported and updated with further painting.
My character is setup as a Humanoid. Even if I export the character as an obj with an obj key, sculpted morph layers in Zbrush without changing vertex count and poly group, CC4 crashes when I click on import using the obj import morphs panel with the obj key assigned. When I export with smoothing, it adds to the file size, same with enabling groups but either way, it gives no warning and crashes. I've exported with various settings shown in the image. Grps should not need to be enabled since CC4 exports the obj as one group I've tried looking for a Zbrush tutorial that may show me something I might have missed but I haven't found anything, but still, maybe CC4 should tell us what the error is specifically whether incorrect vertex count etc.