There are cases where WinDBG fails to detect runtimes in the process. In doing so, it won't load SOS. There's also cases where SOS won't enumerate all modules as it is too expensive and might miss runtimes. We need a clearer UX around these scenarios. Right now it's a very unhelpful:
CLRDLL: ERROR: Unsupported mscor DLL type mscoree
CLR DLL status: ERROR: Unsupported mscor DLL type mscoree