It took me a few days before I finally found what updates were affecting my WSE3 project setup.
We are building a webservice with Web Service Extensions 3 and actively testing that from a unittest project, which also sends WSE3 soap requests.
However, lately, suddenly the requests where not sent and we saw the following exceptions:
System.IO.IOException : Unable to write data to the transport connection: An established connection was aborted by the software in your host machine.
—-> System.Net.Sockets.SocketException : An established connection was aborted by the software in your host machine
After looking through my Control Panel -> Add remove programs -> "Show updates" I saw two updates that were automatically installed by Microsoft. These are:
KB958481 for the Microsoft .NET 2.0 framework and
KB958483 for the Microsoft .NET 3.5 framework
After removing those updates, the unittest project was working again, or in other words: able again to communicate with WSE3 to our local running webservice…
I Hope this helps out others in the .NET community,