problems in engineering data:(

[Fabio89]

Hello, guys.
I have no idea how it could happen but when I go to open the material library, I get this red x...
How do I restore the material library?Thank you very much for the future suggestions

 

[gerod]

Never happened!
Can you restore? Now I don't have the license and I can't see but you can restore the library, at least I have already done it for an old version.
Hi.

 

[Fabio89]

I thought about it, but I still can't do it I'm sure I'm wrong.