Flo Wittmann

Well, I'm having the same issues and couldn't resolve it either, but as far as I can tell it seems to be Intel GPU and driver related. Some gyu over at the Intel forums was able to fix it by not using the latest driver but some version around 25.20.xxx.xxxx. I don't know what your system specs are, but if everything was working for you till this morning you should be able to restore your system to a previous state, or install older drivers.

- Found another reference to this problem in the dell forums - if you're using one of their XPS laptops with intel graphics (HD 630 i.e.) you could try this driver: “25.20.100.6583, A06”

Any chance you are using a Intel GPU? If so, you could try to roll back to a earlier driver (25.xxx.xxx i.e.) if possible.

Actually yes, at least I think so - Problem was I used ‘Collapse Selected into Material’ from the Edit menu which also automatically connected the core shader to a displacement export - and those variables seem to only be valid in ‘Surface’ Context (which absolutely makes sense of course). So as soon as I deleted the displacement export the warning went away… Strange, that a menu operation would setup it in such a way though - maybe I'm missing something else? Let me know if its the same for you, cheers