Here is a free program to check the Nikon D850 shutter count (Windows only) - Nikon Rumors
Checking Shutter Actuations On Your Canon DSLR Camera | Marc Schultz
Shutter Count Program for Windows - zip file: This is a zip file containing an old free version of the shutter count application for Canon DSLR cameras - It runs on Windows, certainly...
Shutter count - how and why to check the shutter count of your camera
ShutterCheck - Check Shutter Count of Your Canon EOS Camera
How to find shutter count on Canon DSLR for free — MAC | Clay Duda