Ensure your graphics drivers are up-to-date, as outdated drivers can cause compatibility issues. You can check for updates on:
Koikatsu uses a launcher (InitSetting.exe) to manage graphics. If you bypassed it or it crashed, your resolution may be set to something your monitor doesn't support.
Before diving into registry edits or file hunting, try these three fixes first. They solve 60% of all crashes.
1. Run as Administrator and Set High DPI
2. Disable Fullscreen Optimizations
3. Install the Latest Visual C++ Redistributables
Ensure your operating system is up to date. Sometimes, older versions of Windows or other OS might have compatibility issues with newer games.