Errors after migration from 2.0M6 to RC1

Hi,
everytime I start or after build/make in MPS2.0RC1 I get about 500 error messages saying things like

[jetbrains.mps.smodel.DefaultScope] Can't find module jetbrains.mps.baseLanguage.unitTest.lib in Scope of module ...

Messages differ in the scope module. It seems like there are almost all modules listed. (including mine and e.g. jetbrains.mps.xmlSchema etc...)

Any idea?