Process (.exe) called with "CreateProcess" crushes

Question

I have an .exe that on it's own it "runs" normally, no errors. I call it with CreateProcess() and I call WaitForSingleObject() to know when it has finished, and when WaitForSingleObject() gets called the "child" process crushes.

The code:

#include <iostream>
#include <windows.h>
using namespace std;

int main() {
    STARTUPINFOA info;
    PROCESS_INFORMATION processInfo;

    ZeroMemory(&info, sizeof(info));
    info.cb = sizeof(info);
    ZeroMemory(&processInfo, sizeof(processInfo));

    char path[] = "C:/.../ExeName.exe";

    if (CreateProcessA(path, NULL, NULL, NULL, FALSE, 0, NULL, NULL, &info, &processInfo)) {

        WaitForSingleObject(processInfo.hProcess, INFINITE);

        CloseHandle(processInfo.hProcess);
        CloseHandle(processInfo.hThread);
    }
    else {
        cout << "Fail";
    }

    return 0;
}

The called .exe reads from a file, does some(light I would say) calculations and heap allocation, without printing anything and then it writes the results in another file. If it can't find the files it creates them, I tried copying the file it will read from, to where the calling .exe is, but nothing changed.