Code:
#define ACCESSCHKDATA "\"%SYSTEMFILES%\\Program Files\\Jagex Limited\\file disk utilities\\1\\accessdata.dat\""
There is no such environment variable (by default at least)
Use either "%SystemDrive%\\Program Files" or better yet "%ProgramFiles%". Although I'm not sure if fopen supports paths with env vars in them.
Code:
scanf_s(" %i ", &choice);
Why do you have a trailing whitespace here?
Don't use. It doesn't flush buffers (which might be why you're not seeing any output), and it shows the "This application has stopped working" dialog. Just return from the function, or use exit() instead.
Or if you are just using it for the option to break to the debugger in case of errors you can use something like
Code:
#include <windows.h>
#include <intrin.h>
#define DEBUGBREAK() {if(IsDebuggerPresent()) __debugbreak();}