While building a unit test project, VS 2010 cannot find the referenced assembly for testing

Question

I'm developing a unit test project (let's say XXX.UnitTest) to test ViewModels in another project (XXX) in my solution. I can add the reference but when I build, an error states that it cannot find that same project (XXX)

Error 42 Could not load file or assembly 'XXX, Version=1.0.2.66, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified. XXX.UnitTest

• I did a clean rebuild of all projects in my solution.
• I verified that the assembly with that version number (1.0.2.66) did exist in the path I was referencing.
• I removed and re-added the reference both as a project and through the Browse tab.
• I made sure that the version number was not specified in the csproj file.
• I verified the referenced assembly with Dependency Walker.
• I verified that both projects were targeting the x86 platform. (As suggested here Tips to help debug "Could not load file or assembly X or one of its dependencies")

Does anyone know what else can cause this problem?

Answer 1

Last week I had this same problem. It turns out my solution and projects were on a network resource. If I moved the solution to the local drive, the problem went away.

• This problem happened regardless if I used a mapped drive or an UNC path.

• This problem happened even with a Code Access Security Policy of "Full Trust" for the URL.

• I believe the problem occurs on Windows XP computers and not Windows 7 computers, but have not tested or verified.

• I believe it has something to do with the Share permissions.

  • If I try to use "offline folders" for the network resource, I get "access is denied".

  -.

• Setting NTFS permissions has no effect.

• Adding user to administrators group has no effect.

• I did not test to see if problem exists on removable local drives.

Work Around

Move solution and projects to a local hard drive.

Comment

I think this is a bug in Visual Studio 2010.