Crash after importing Skeleton Mesh

After importing a Skeleton Mesh from a car model prepared and rigged in Blender Unreal crashes. It crashes when saving the project after importing, not during the importing. So importing seems to be right but saving seems to be the problem. In explorer I can see none of the assets are in the folder. After the crash everything is gone.

Importing the same model as Static Mesh is not a problem.

Any ideas how to solve this problem?

Having the same problem, have you managed to find what causes it ?