I'm getting a "Member not found" error with VS2013 Update 2 (either RC or RTM) in the Solution Explorer, with my SSDT database projects. I also get errors when adding new files to my database project, as well as when changing the values of various file properties (e.g. changing the Build Action to "none").
The errors occur if I have an AssemblyInfo.cs file in the project, i.e. in projects where I am deploying SQLCLR. The interesting part is, if I change the AssemblyInfo.cs file build action to None, then close and re-open the solution, I no longer get the error.
EDIT 2014-06-11: As mentioned by Lawrence Smith, the issue occurs if there are any .cs files in the database project at all, i.e. it is not limited to just the AssemblyInfo.cs file. To work-around the issue, you need to set all .cs files Build Action to "none".
A number of customers have reported this issue, who have also upgraded to VS2013 Update 2.
Here are some of the errors I am receiving in the Solution Explorer/Properties window:
* Exception has been thrown by the target of an invocation.
* An unexpected exception was encountered: The project item was not created.
* Not implemented (Exception from HRESULT: 0x80020001 (E_NOTIMPL)).
* Member not found. (Exception from HRESULT: 0x80020003 (DISP_E_MEMBERNOTFOUND)).