[4.8/4.9] Engine crash on opening project

Project is purely blueprints no custom C++ code or plugins. Started crashing after I’ve disabled static lighting and I think I’ve changed Project Settings-> General Settings->Preview Shadows Indicator Material to clear from “PreviewShadowIndicatorMaterial” default and I wasn’t able to set it back. After this I can’t re-open project in both 4.8 and 4.9.
Full content of AppCrash folder:

Found that setting in DefaultEngine.ini and manually fixed it to default. Now I can open project. But perhaps it’s useful for you guys for debugging, I’ll keep crash report available online.