WCF – ____ is already defined.

This drove me crazy for a several hours. Turned out the solution was simple. Again MS has limitations that don’t allow combinations of input / output. YOu have either use wrappers or no wrappers. It seems like I have seen implementations where this limit did not exist, but putting wrappers (reauest / response) around my new entry points fixed the issue.

More info at stack overflow:

wcf – Add Service Reference “___ is already defined”a – Stack Overflow