Finally got home to try the command and got this log output:
RetroArch [INFO] :: === Build =======================================RetroArch [INFO] :: [CPUID]: Vendor: GenuineIntel
RetroArch [INFO] :: [CPUID]: Features: MMX MMXEXT SSE SSE2 SSE3 SSSE3 SSE4 SSE4.2 AES AVX
MMX MMXEXT SSE1 SSE2 SSE3 SSSE3 SSE4 SSE4.2 AVX AES Built: Jul 19 2015
RetroArch [INFO] :: Version: 1.2.2
RetroArch [INFO] :: Git: f073739
RetroArch [INFO] :: =================================================
RetroArch [INFO] :: [CPUID]: Vendor: GenuineIntel
RetroArch [INFO] :: [CPUID]: Features: MMX MMXEXT SSE SSE2 SSE3 SSSE3 SSE4 SSE4.2 AES AVX
RetroArch [WARN] :: screenshot_directory is not an existing directory, ignoring …
RetroArch [WARN] :: system_directory is not set in config. Assuming system directory is same folder as game: “”.
RetroArch [INFO] :: Loading config from: C:\Emulators\RetroArch_1.2.2\retroarch.cfg.
RetroArch [INFO] :: Environ SET_PIXEL_FORMAT: RGB565.
RetroArch [INFO] :: Version of libretro API: 1
RetroArch [INFO] :: Compiled against API: 1
RetroArch [INFO] :: Set audio input rate to: 29975.00 Hz.
RetroArch [INFO] :: Video @ 960x720
RetroArch [INFO] :: Found GL context: wgl
RetroArch [INFO] :: Detecting screen resolution 1680x1050.
RetroArch [INFO] :: [GL]: Vendor: Microsoft Corporation, Renderer: GDI Generic.
RetroArch [INFO] :: [GL]: Version: 1.1.0.
Anyone got a clue?