I managed to split the scene in two and open parts of it first and import the rest as a prefab. I deleted most of the actions and built the level. Anyway I have gone back to 6.4. Will wait until the beta is the new version. My experience with 6.4 is also somewhat strange concerning rendering. Pixelation around objects, strange "jumping" movements by entities and player.
I guess I have to build everything from scratch again if I want to get this to work.
A bit depressing as I have 7 levels. Beem working on it for 3 years and am dead tired of upgrading. But I do need some of the new functionality.
hanks for taking an interest..