I had a crash when converting an existing project. Here is the minimum repro case I could come up with:
1: Make a new project, no started content needed.
2: Go to project settings-> rendering and uncheck “occlusion culling” and “dbuffer decals”.
3: You will be asked to restart the editor. Click restart now. After the editor restarts it will crash and trying to open the project onward will crash the editor.
I tested this in 4.16 and it does not crash with that version.
Some background information that may be useful:
I had a project that I converted to 4.17. That project didn’t crash on startup but only when I started the static mesh editor. In the callstack it said that the error was somewhere in the postprocessing pipeline and reflective environment. As I disabled a lot of the postprocessing effects and other stuff in the current loaded map I figured that it could be the culprit (as the static mesh editor has his own postproces settings independent of the loaded map). After some trial and error I noticed that by enabling dbuffer decals I was able to open the static mesh editor again.