If you dont get the chance to alt+enter as cold suggests there is one other way, and thats to edit in the registry:I need a little help here. I have a very old Laptop on which I play my games. Due to this my graphic drivers are now considered legacy and therefore most of the unity games crash to desktop with an error window. I have noticed that those same games can run on my system if they are in windowed mode instead of fullscreen. Problem is this game does not have a launcher for me to configure it. Is there a way to force start unity games in windowed mode?
hit windows key + R, type in regedit,
find the folder Computer\HKEY_CURRENT_USER\SOFTWARE\VNGINE\Timestamps: Unconditional Love
find key Screenmanager Fullscreen mode_[some numbers]
change value to 3 instead of 1.
I just tested it and can confirm that it works.