Windowed/fullscreen mode toggle does not run in when launching a packaged windows .exe

I have a project that refuses to go to the windowed mode when I’m running the packaged Windows .exe file. However, when launching the project from the Unreal Editor, the windowed mode DOES work (the normal ALT+Enter or F11, plus an additional trigger for ESC key that I added).

Works:

  1. Choose “Launch” for my project in Unreal Editor → Game opens in windowed mode

  2. Press ALT+ Enter → Game goes to full screen mode

  3. Press ALT+ Enter → Game goes to windowed mode

Does NOT work:

  1. Package the .exe for windows (File->Package->Win 64 bit)

  2. Locate the .exe file and launch it → Game opens in Fullscreen mode

  3. Press ALT+Enter → Game stays in full-screen mode, I can see the windows task bar “flicker” though.

Some help for troubleshooting would be great!

I had the same problem in UE 4.18.3 as well. I think the problem is that it doesn’t know which resolution to use. After changing the resolution once (see picture below), the problem went away for me.

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