Unit test in visual studio looks for a version of a dll that does not exist. QualityTools.UnitTestFrameWork 12.0.0.0

I have this wierd problem, and it only appears after when I add a second Test Class and add some code to it.

It works fine before I add the second testclass and it works fin until I add som more code to the second testclass. I cant make out what triggers this problem but the following appears:

Error loading C:\Tfs\Test\AcceptanceTest\OrganizationServiceTests\OrganizationServiceV2Tests\OrganizationServiceTest\bin\Debug\OrganizationServiceV2Tests.dll: Could not load file or assembly 'Microsoft.VisualStudio.QualityTools.UnitTestFramework, Version=12.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.

Its a unit test.

It is looking for a 12.0.0.0 version of qualitytools.unittestframework, What I can make out of it, there is only up to version 10.0.0.0. Everywhere I look there is no reference to this version. All references refer to 10.0.0.0 So I have no idea where this comes from.

Is there anyway to further debug this or anyone know what problem this could be?

This is what the dll looks like:

// Microsoft.VisualStudio.QualityTools.UnitTestFramework, Version=10.0.0.0,        Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a

// Architecture: AnyCPU (64-bit preferred)
// Runtime: .NET 2.0

using System;
using System.Diagnostics;
using System.Reflection;
using System.Resources;
using System.Runtime.CompilerServices;
using System.Runtime.ConstrainedExecution;
using System.Runtime.InteropServices;
[assembly: AssemblyVersion("10.0.0.0")]
[assembly: CLSCompliant(true)]
[assembly:     Debuggable(DebuggableAttribute.DebuggingModes.IgnoreSymbolStoreSequencePoints)]
[assembly: AssemblyCompany("Microsoft Corporation")]
[assembly: AssemblyCopyright("© Microsoft Corporation. All rights     reserved.")]
[assembly:     AssemblyDefaultAlias("Microsoft.VisualStudio.QualityTools.UnitTestFramework.dll")]
[assembly: AssemblyDelaySign(true)]
[assembly:     AssemblyDescription("Microsoft.VisualStudio.QualityTools.UnitTestFramework.dll")    ]
[assembly: AssemblyFileVersion("12.0.30723.0")]
[assembly: AssemblyInformationalVersion("12.0.30723.0")]
[assembly: AssemblyKeyFile("f:\\dd\\tools\\devdiv\\FinalPublicKey.snk")]
[assembly: AssemblyProduct("Microsoft® Visual Studio® 2013 ")]
[assembly: AssemblyTitle("Microsoft.VisualStudio.QualityTools.UnitTestFramework.dll")]
[assembly: NeutralResourcesLanguage("en-US")]
[assembly: SatelliteContractVersion("10.0.0.0")]
[assembly: CompilationRelaxations(8)]
[assembly:     InternalsVisibleTo("Microsoft.VisualStudio.QualityTools.Tips.UnitTest.Adapter,     PublicKey=002400000480000094000000060200000024000052534131000400000100010007d1fa    57c4aed9f0a32e84aa0faefd0de9e8fd6aec8f87fb03766c834c99921eb23be79ad9d5dcc1dd9ad2    36132102900b723cf980957fc4e177108fc607774f29e8320e92ea05ece4e821c0a5efe8f1645c4c    0c93c1ab99285d622caa652c1dfad63d745d6f2de5f17e5eaf0fc4963d261c8a12436518206dc093    344d5ad293")]
[assembly: InternalsVisibleTo("MS.TLM.Test.TE.LegacyDC.TestHelpers.Common,     PublicKey=002400000480000094000000060200000024000052534131000400000100010057c60b    06ff787f4e7584af1d49e4ec20b109b1e200b97688b4ce376b11f91652ee69f3e57388a4ea13380d    37ef7921c38f0797f4ae1508884531b8847a89856207f67b0b833a950169a35b37e57b107cd985ea    0deda6177ad2213ed5751161262c28f37a4d4312db785177bfd08be4a961636f9359211c3be188f6    4ddca934a8")]
[assembly:     InternalsVisibleTo("MS.TLM.Test.TE.LegacyDC.UnitTestFrameworkTest,     PublicKey=002400000480000094000000060200000024000052534131000400000100010007d1fa    57c4aed9f0a32e84aa0faefd0de9e8fd6aec8f87fb03766c834c99921eb23be79ad9d5dcc1dd9ad2    36132102900b723cf980957fc4e177108fc607774f29e8320e92ea05ece4e821c0a5efe8f1645c4c    0c93c1ab99285d622caa652c1dfad63d745d6f2de5f17e5eaf0fc4963d261c8a12436518206dc093    344d5ad293")]
[assembly:     InternalsVisibleTo("Microsoft.VisualStudio.TestTools.TestGeneration,     PublicKey=002400000480000094000000060200000024000052534131000400000100010007d1fa    57c4aed9f0a32e84aa0faefd0de9e8fd6aec8f87fb03766c834c99921eb23be79ad9d5dcc1dd9ad2    36132102900b723cf980957fc4e177108fc607774f29e8320e92ea05ece4e821c0a5efe8f1645c4c    0c93c1ab99285d622caa652c1dfad63d745d6f2de5f17e5eaf0fc4963d261c8a12436518206dc093    344d5ad293")]
[assembly:     InternalsVisibleTo("Microsoft.VisualStudio.TestPlatform.Extensions.VSTestIntegra    tion,     PublicKey=002400000480000094000000060200000024000052534131000400000100010007d1fa    57c4aed9f0a32e84aa0faefd0de9e8fd6aec8f87fb03766c834c99921eb23be79ad9d5dcc1dd9ad2    36132102900b723cf980957fc4e177108fc607774f29e8320e92ea05ece4e821c0a5efe8f1645c4c    0c93c1ab99285d622caa652c1dfad63d745d6f2de5f17e5eaf0fc4963d261c8a12436518206dc093    344d5ad293")]
[assembly:     InternalsVisibleTo("Microsoft.VisualStudio.TestTools.TestGenerationDialog,     PublicKey=002400000480000094000000060200000024000052534131000400000100010007d1fa    57c4aed9f0a32e84aa0faefd0de9e8fd6aec8f87fb03766c834c99921eb23be79ad9d5dcc1dd9ad2    36132102900b723cf980957fc4e177108fc607774f29e8320e92ea05ece4e821c0a5efe8f1645c4c    0c93c1ab99285d622caa652c1dfad63d745d6f2de5f17e5eaf0fc4963d261c8a12436518206dc093    344d5ad293")]
[assembly: RuntimeCompatibility(WrapNonExceptionThrows = true)]
[assembly: ReliabilityContract(Consistency.MayCorruptInstance, Cer.None)]
[assembly: ComVisible(false)]

Really have no idea where it sets the version to 12.0.0.0,

Kind regards

Fredrik