Trying to get back to ZBrush. I had a CustomUserInterface35.cfg file, which I developed in 3.5 and used in 4.0 and 4.2. Always, the CUI was active as long as the file was located in the second level folder (i.e., …Pixologic\ZBrush4R2). However, I can’t get it to work with 4R3 nor can I load it manually from Preferences. (I have also tried placing the .cfg file in ZStartup. No dice.) Any help would be much appreciated.
That file will not be compatible with version 4R3. There have simply been too many changes to both ZBrush’s features and its UI organization. You will need to create a new CustomUI.
I had the same issue
but here the solution is