Make a Build and Run of a Webplayer with any project (even completely empty one). As soon as that is finsihed you will get this assert printed twice in the Console:

ok
UnityEditor.BuildPipeline:BuildPlayerInternalNoCheck(String[], String, BuildTarget, BuildOptions, Boolean, UInt32&)
UnityEditor.BuildPlayerWindow:BuildPlayerWithDefaultSettings(Boolean, BuildOptions, Boolean) (at C:\BuildAgent\work\afa2580bf6048259\Editor\Mono\BuildPlayerWindow.cs:757)
UnityEditor.BuildPlayerWindow:BuildPlayerWithDefaultSettings(Boolean, BuildOptions) (at C:\BuildAgent\work\afa2580bf6048259\Editor\Mono\BuildPlayerWindow.cs:588)
UnityEditor.BuildPlayerWindow:GUIBuildButtons(Boolean, Boolean, Boolean, BuildPlatform) (at C:\BuildAgent\work\afa2580bf6048259\Editor\Mono\BuildPlayerWindow.cs:1614)
UnityEditor.BuildPlayerWindow:ShowBuildTargetSettings() (at C:\BuildAgent\work\afa2580bf6048259\Editor\Mono\BuildPlayerWindow.cs:1571)
UnityEditor.BuildPlayerWindow:OnGUI() (at C:\BuildAgent\work\afa2580bf6048259\Editor\Mono\BuildPlayerWindow.cs:1147)
System.Reflection.MonoMethod:InternalInvoke(Object, Object[], Exception&)
System.Reflection.MonoMethod:Invoke(Object, BindingFlags, Binder, Object[], CultureInfo) (at /Users/builduser/buildslave/monoAndRuntimeClassLibs/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:222)
System.Reflection.MethodBase:Invoke(Object, Object[]) (at /Users/builduser/buildslave/monoAndRuntimeClassLibs/build/mcs/class/corlib/System.Reflection/MethodBase.cs:115)
UnityEditor.HostView:Invoke(String, Object) (at C:\BuildAgent\work\afa2580bf6048259\Editor\Mono\GUI\DockArea.cs:241)
UnityEditor.HostView:Invoke(String) (at C:\BuildAgent\work\afa2580bf6048259\Editor\Mono\GUI\DockArea.cs:234)
UnityEditor.HostView:OnGUI() (at C:\BuildAgent\work\afa2580bf6048259\Editor\Mono\GUI\DockArea.cs:126)

[C:/BuildAgent/work/afa2580bf6048259/PlatformDependent/Win/File.cpp line 961]
(Filename: C:/BuildAgent/work/afa2580bf6048259/Editor/Mono/BuildPlayerWindow.cs Line: 757)

This is a regression from Unity 4.5 a5.