This connect bug describes an issue with creating certain types of Silverlight projects in Visual Studio. If you're referencing Silverlight 4 DLLs from a Silverlight 5 project, you may run into this code analysis/FXCop issue yourself if code analysis is part of your process. The core of the problem is a versioning decision in Silverlight 5 which results in compile-time violation due to loading two different versions of mscorlib in the same project. It manifests as the following error:
- Error 2 CA0055 : Could not unify the platforms (mscorlib, Version=18.104.22.168, Culture=neutral, PublicKeyToken=7cec85d7bea7798e, mscorlib, Version=22.214.171.124, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) for 'MyProject.Silverlight\obj\Debug\MyProject.dll'.
How to Reproduce the Issue … in theory
In theory, all you need to do to reproduce the issue is reference a SL4-targeted DLL from an SL5 application. However, in practice, there are other factors in play. For example, it may matter which mscorlib version gets loaded first.