Today I got bit with an issue with published applications (via RemoteApp). Clients were complaining about RDP.
You could connect to the server, run the application from there, but you could not run the application that has been published by RemoteApp.
I have checked everything but updates that came last night... so it took us like hours to find out what is going on. So for those you are using Windows Server 2008, and have problems with the published apps (via RemoteApp) get rid of " Update for Microsoft Windows (KB3004394)" which came 10.12.2014 and apps should be running smoothly.
Hope this will help someone.