Ran into an issue where the GoZ button in CC4 would not bring up any dialogue window and the solution was two parts:
1.Removing any existing registry entries for versions of Maxon ZBrush that were no longer installed on the machine under
HKEY_LOCAL_MACHINE\SOFTWARE\Maxon
2. Copying the Character Creator 4 GoZ Plus plugin file/folder from
C:\Program Files\Reallusion\Character Creator 4\Resource\ICGoZBrush\ZBScript
CCGoZ.zsc
CCGoZData
to EVERY installation of ZBrush on the machine
C:\Program Files\Maxon ZBrush {version}\ZStartup\ZPlugs64
When I had the plugin installed in only one version of ZBrush it wouldn't work. Wasn't until I copied it to every version (2022, 2023, 2024) that the dialogue window started showing up for me.