I have a few things for you to try and a few things I need from you for some more information if those don’t work.
First, open up the Edit > Project Settings > Maps & Modes menu and set a map of your choice for the “Game Default Map” if there isn’t one already set.
When going to open your project, please ensure that you’re attempting to open the .exe located at DemoFinale\WindowsNoEditor which matches the name of the project and not the UE4game.exe located deeper within those directories.
Try making a copy of the project and removing the assets that are causing these warnings one by one to see if, by trial and error, you can find the assets that are causing the issues. Sometimes this is the easiest way to figure out what the problem is.
If none of these help, please take screenshots of the following windows for me so that I can at least try to recreate what you’re running into.
-The Maps & Modes window, with the top settings field expanded
-The Packaging settings window (Inside of Project Settings) with the bottom settings field expanded, showing the list of maps to cook
-The error message that you get whenever you try to open the packaged project