I ran into this error message while trying to debug a project today:
“Duplicate type name within an assembly.”
The workaround to this was actually pretty weird. Remove all of your breakpoints that appear before this exception and place one after it instead. That’s it!
A bit of a weird issue, but according to the StackOverflow post where I found the solution Microsoft are aware of it: http://stackoverflow.com/a/23529882/522859