.NET Framework 3.5 Client Profile - Missing method System.Windows.Threading.Dispatcher.BeginInvoke(System.Delegate, System.Object[])

My application targets the .NET Framework 3.5 client profile and my setup is configured to install this framework using the online installer, but sometimes (at 3 users out of 12000) the application throws the following exception:

Method not found: 'System.Windows.Threading.DispatcherOperation System.Windows.Threading.Dispatcher.BeginInvoke(System.Delegate, System.Object[])'

I also receive the following warning from the Visual Studio 2010 Code Analysis tool:

Warning CA1903 : Microsoft.Portability : Member 'Settings.SearchForApplicationRelease_bgWorker(object, DoWorkEventArgs)' uses member 'Dispatcher.Invoke(Delegate, params object[])'. Because this member was introduced in.NETFramework 3.0 Service Pack 2, which was not included in t开发者_C百科he project's target framework, .NET Framework 3.5, your application may fail to run on systems without this service pack installed.

I have tried on several systems but I am not able to reproduce this exception.

How can I fix it?

Are there any chances that the users have a corrupt version of the .NET Framework?

Thanks, Cosmin

Microsoft documentation states this method is compatible with .NET 3.0 and up. However Micosoft .NET 3.5 sp(0) ->Not service pack 1<- is broken and does not support any BeginInvoke methods. There are other issues with .NET 3.5 sp(0) and it should be removed from existance. You will have to force the update to .NET 3.5 sp(1) for this method to work.