When I import an asset in Unity 2017.3 the material is not created in the ressources

Since I have updated to Unity 2017.3 when I export an asset from Blender to Unity the material is detected, all my textures are connected automatically but the material isn't created in the ressources, before it was. Every time I add a new asset I must recreate the material and reattach the textures. How can I setup Unity to automatically create the material in the ressources like before?

 

Same problem here..

 

Unity changed some options regarding model materials.
https://docs.unity3d.com/Manual/FBXImporter-Materials.html
Use Embedded Materials Choose this option to extract imported Materials as external Assets. This is the default option from Unity 2017.2 onwards.
Use External Materials (Legacy) Choose this option to keep the imported Materials inside the imported Asset. This is a Legacy way of handling Materials, and is intended for projects created with 2017.1 or previous versions of Unity. This is the default option for Unity 2017.1 and previous versions of Unity.

Does this have to do with your issue?