Running mednafen without a ROM file loaded will simply return you to the command line. in the prompt, and a dialog window showing the same message. AmatCoder commented Aug 5, 2018 Mednafen is installed, of course - I can run it fine from the command line. level 1 It's a command line program. 0) 0000-00-00 Compiled against zlib 1.2.8, running with zlib 1.2.8(flags=0x00000065) Compiled against libiconv 15.1, running with libiconv 15.1 Compiled against SDL 2.0.8(hg-11835:f622a4457a25), running with SDL … Error: No mednafen configuration file found. mednaffe 0.8.8 Mednafen 1.21.1 x64 Windows 7 64-bit.

Mednafen is a command-line based emulator, but you could use either RetroArch or some other frontend.
It is doing what it is supposed to. Starting Mednafen 1.21.1 Build information: Compiled with gcc 4.9.4 Running with MinGW-W64 Runtime 5.0 (alpha - rev. When you do push F1, you will see a window pop over whatever emulated game is running inside your mednafen graphical window.