The "Executable Not Found" error typically occurs when the game client or launcher is unable to locate the game's executable file. This can happen due to several reasons:

As you can see, the game requires a relatively powerful system to run smoothly, especially with high-quality graphics. If your system does not meet these requirements, you may encounter the "Hitman 3 Executable Not Found Direct3d 12 High Quality" error.

Alternatively, uninstall the high-res pack via Steam/Epic DLC management.

Go to Discord User Settings > Game Overlay > Toggle "Enable in-game overlay" to OFF.