Error found.
In “Level Instances” I had developed houses Modula, which I had converted into proxy meshes to reduce the loading of materials, M-instances and textures.
The “level instance” was probably damaged because I was warned that the instance refers to an external object.
Since I don’t currently use C++ objects, this seemed strange to me.
I put the buildings on the map and deleted the “level instances”.
Then I was able to unpack the project problem.
I hope this helps others who have a similar error. Look carefully at the warning.
Another bug solved and the next one will surely come soon.