I know this is a super old thread, but for particular reasons, I needed to use the ini method to set my app to start in a windowed mode. Using 4.24, I can confirm that adding a “DefaultGameUserSettings.ini” (don’t forget “Default” in the file name) using the file content that **Fuchs **suggested did indeed make my app start in windowed mode. HOWEVER, before you do a new package build, make sure you delete your intermediate folder first.