First of all I have to apologize about my lack of knowledge in Solidworks. I am but a mere IT person whom was asked a question by an engineer and am looking for an answer.
My user is having an issue creating custom materials in a custom library.
Here is what he is telling me he has done. He creates a custom library and various categories in it. After that he selects a material from the regular Solidworks library and copies it. He tries to paste that into one of his categories in the custom library. It goes in fine. When he goes to edit it, he gets errors and it reverts back to what it orginally was.
I know this isn't a great description, but it's all I have to work on. If you need more information, I can try and pry it out of him.
Thanks so much in advance.