Thank you very much for the detailed reply!

Copying mentioned dlls indeed fixed explorer startup. Except the start menu which doesn't open for some reason.
Now I'll try to build the thing myself using your instructions.

Hello! Recently I tried to test explorer replacement for Win7, but failed to do that. The problem is that ReactOS's explorer.exe from autobuilt ISO's doesn't start on Windows due to some missing imports. Also I believe it was built without WIN7_COMPAT_MODE macro defined. So my question is, how can I...