"System.Action claims it is defined" error

Question

I'm building a Silverlight 4.0 application with .NET Framework 4.0, and I'm seeing this error:

Reference to type System.Action claims it is defined in 'c:\Program Files\Reference Assemblies\Microsoft\Framework\Silverlight\v4.0\mscorlib.dll', but it could not be found (CS1684) - c:\Program Files\MSBuild\Seesmic\SDP\Seesmic.Sdp.Utils.dll

In my project I have a reference to the same mscorlib.dll that it's claiming to be defined in. Any ideas?

Answer 1

That's an odd location for a DLL (within the MSBuild directory). Is it possible that it's trying to use a reference to a desktop assembly from within your Silverlight application? Admittedly with the assembly portability in v4 I'd half expect that not to be a problem, but it's worth looking into.

If you could give more details about how you're building and where Seesmic comes into the frame, that would help.