Unable to build in Unity 5.5.0b

Hello everybody,
I have recently updated my project to Unity 5.5.0b and the editor does not allow me to build it anymore. When I get to the Build menu, choosing “Build” makes the file selection window pop up, but, after choosing the name of the new file, nothing happens.
I think that this might be related to a MissingMethodException that I am getting and that seems to depend on a Mono Framework file: MissingMethodException: Method not found: 'UnityEditor.PlayerSettings.InitializePropertyInt'. UnityEditor.Modules.ModuleManager.InitializePlatformSupportModules () (at C:/buildslave/unity/build/Editor/Mono/Modules/ModuleManager.cs:199)
Is there any hope of determining what’s wrong and fixing it? Do you suggest that I downgrade my project to 5.4?
Thank you for your help.

Same thing happened with me
I reimported 3 times and then saved the project
close unity
open it again and open your project again
Worked for me