Seeing a "found too many .rd files" error when deploying an Azure project on Dev Fabric

Question

I have a Windows Azure project that has been working and continuously developed for a long time. Suddenly, on my computer, but noone else's on the project, when I run it in the dev fabric, it builds correctly, but then when it gets to the "Deploying package to the Windows Azure compute emulator" it throws an error of "Found too many .rd files" and stops.

There are not many references to this that I can find, but those that are out there suggest deleting and re-creating the csdef and cscfg files (I've done that, no luck), or looking for other config related issues. I've stopped/started the compute emulator, rebooted, pulled a fresh version of the code from Git, etc, and nothing seems to work. Noone else on the team is experiencing this.

If I manually run CSPack and CSRun from a command prompt, the same error does appear. If I do that, but then after the CSPack, I delete the ServiceDefinition.rdsc file in my output directory, it does run the app without the error, but no longer knows my config settings, and does not allow breakpoints in Visual Studio, obviously, so that's not a good option.

I'm stumped, any ideas where to go next?

Steve