Is not clear for me what you try  with 3d xchange  and why.
For creating custom morph you should follow the description 

Custom Morph Slider

http://wiki.reallusion.com/Content_Dev:CC_Morph_Creation



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liebe Grüße vidi

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So here is the process I did.  I exported a Character from Character Creator in .fbx format.  I used the Maya settings for the export.  I made changes to the model using Maya and Mudbox but now when I import it back in I get the attached error.  I have purchased export licenses for the character.  It created the .fbx key file as well but it won't let me import.  The only thing I changed was the mesh by adding a little more fat to the face and some added to the cheeks.  I didn't do anything with the eyes or the rigging.  Any ideas of what my workflow is supposed to be if I want to do small mesh changes to these characters to be able to import them back in?