Unity 3 Build and Build & Run does not work, why?

Hello there, I wanted to test the game and build it, but I can't. If I press Build or Build&Run for Windows I get the following error shown and nothing else happens.

Could someone help me out? Thank you

MissingMethodException: Cannot find the requested method. UnityEditor.BuildPlayerWindow.BuildPlayerWithDefaultSettings (Boolean askForBuildLocation, BuildOptions forceOptions, Boolean first) (at C:/BuildAgent/work/300357e52574df36/Editor/Mono/BuildPlayerWindow.cs:428) UnityEditor.BuildPlayerWindow.BuildPlayerWithDefaultSettings (Boolean askForBuildLocation, BuildOptions forceOptions) (at C:/BuildAgent/work/300357e52574df36/Editor/Mono/BuildPlayerWindow.cs:412) UnityEditor.BuildPlayerWindow.GUIBuildButtons (Boolean enableBuildButton, Boolean enableBuildAndRunButton, Boolean canInstallInBuildFolder) (at C:/BuildAgent/work/300357e52574df36/Editor/Mono/BuildPlayerWindow.cs:1222) UnityEditor.BuildPlayerWindow.ShowBuildTargetSettings () (at C:/BuildAgent/work/300357e52574df36/Editor/Mono/BuildPlayerWindow.cs:1203) UnityEditor.BuildPlayerWindow.OnGUI () (at C:/BuildAgent/work/300357e52574df36/Editor/Mono/BuildPlayerWindow.cs:899) System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) Rethrow as TargetInvocationException: Exception has been thrown by the target of an invocation. System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) UnityEditor.HostView.Invoke (System.String methodName, System.Object obj) (at C:/BuildAgent/work/300357e52574df36/Editor/Mono/GUI/DockArea.cs:228) UnityEditor.HostView.Invoke (System.String methodName) (at C:/BuildAgent/work/300357e52574df36/Editor/Mono/GUI/DockArea.cs:221) UnityEditor.HostView.OnGUI () (at C:/BuildAgent/work/300357e52574df36/Editor/Mono/GUI/DockArea.cs:121)