SU2017: Validitiy Check can't fix Problems

Saving the model tells me that there are problems that can’t be fixed.
I repaired SU twice, but no result.
The first Blug Spot came by changing the axis in an octagon.
The second Blug Spot I don’t remember.
After that I couldn’t draw a Polygon witht more than 6 sides, needed 8.
Now I can’t edit Material.
All the screen symbols in Scenes are gone.

How can I rescue my model?

This is the normal behaviour for standard materials, you have to add the desired material to your model materials to be able to edit its properties.

It seems as something in the model was corrupted. Maybe saving it to an older SU version and then open it from that file would help? It would purge some contents such persistent IDs. Just an idea.

That’s what I did. Still working on the same file, but the message is gone. Found some strange hidden geometry in the octagon and erased them.
Something renamed my rafters in “Outershell” ?? and the Polgons still have only 6 sides.

For the next model I will start a new Version of SU.