So I made a head in Blender with facebuilder but I did it on my Macbook. I’m so happy with how it turned out but when I transfer it over to my Blender on my Windows PC, it won’t let me export it to Character Creator 4 and it says “cannot reload current model before start” whenever I press Export to Character Creator. So I’m wondering if the problem is that I made it on my Mac and it isn’t able to work on Windows after? Idk, just wondering if someone out there has had the same problem and if so, how to fix it.
If it’s a FaceBuilder Addon issue, please find information on the link or contact us. 
It’s very unlikely that they use a different file format on windows and mac… so you might check the versions ? Or your transport was somehow corrupted ??