C# compiler error CS0433

Question

Update 1: I have uploaded my project folder to dropbox - dropbox.com/s/8dfw3uprrynrhzx/S3Util.zip

I am new to Visual Studio, and I have created a small Windows Runtime Component in C# on Visual Studio 2012 Express for Windows 8.

My component consists of a single sealed class, with a single static method. I have added a unit test library project to the solution to test this static method.

(I followed this walkthrough to create a unit test)

When I build the solution, I get the following error:

Error 1     The type 'S3Util.S3Security' exists in both 'c:\workspace\vs\S3Util\S3Util\bin\Debug\S3Util.winmd' and 'c:\workspace\vs\S3Util\S3Util\bin\Debug\S3Util.winmd'
C:\workspace\vs\TestLib_S3Util\TestLib_S3Util\Test_Security.cs 18 27 TestLib_S3Util

The error help page on Microsoft website indicates that it is a Compiler Error CS0433.

However, my unit test library contains only one reference to my windows runtime component project, and even the error message I see is referring to the same .winmd file twice. Kindly help me understand the issue and how to resolve it.

Error screenshot: (click for full size)

Answer 1

In cases when I don't know why the error occurs I'm starting to narrow the list of possibilities. I'd do the following:

1. Look for a class S3Security via search. If you find 2 of them - remove one.
2. Try to remove one of the references were added recently and compile. Remove till the project compiles.
3. Try to remove latest files/projects untill solution compiles with no error. You can also try a reverse move, start to do the stes you were doing and check at which step you will get your error. Let us know what is it.