Cannot create a service reference with namespace XXX becuase the name is already in use by an existing service reference, folder or file

If you get the above error when trying to add a WCF service reference that you have previously deleted then try:

• deleting the Service References.DeviceService.Reference.cs.dll file you'll find under obj\Debug\TempPE. 
• deleting the service folder you'll still find under Service References on disk, even though you deleted the reference in Visual Studio.
• commenting out all references to the service's namespace in your code
• rebuilding