The located assembly's manifest definition doe

Question

I am trying to run some unit tests in a C# Windows Forms application (Visual Studio 2005), and I get the following error:

System.IO.FileLoadException: Could not load file or assembly 'Utility, Version=1.2.0.200, Culture=neutral, PublicKeyToken=764d581291d764f7' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)**

at x.Foo.FooGO()

at x.Foo.Foo2(String groupName_) in Foo.cs:line 123

at x.Foo.UnitTests.FooTests.TestFoo() in FooTests.cs:line 98**

System.IO.FileLoadException: Could not load file or assembly 'Utility, Version=1.2.0.203, Culture=neutral, PublicKeyToken=764d581291d764f7' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

I look in my references, and I only have a reference to Utility version 1.2.0.203 (the other one is old).

Any suggestions on how I figure out what is trying to reference this old version of this DLL file?

Besides, I don't think I even have this old assembly on my hard drive. Is there any tool to search for this old versioned assembly?

Answer 1

I received this error message due to referencing an assembly that had the same name as the assembly I was building.

This compiled but it overwrote the referenced assembly with the current projects assembly - thus causing the error.

To fix it I changed the name of the project, and the assembly properties available through right-clicking on the project and choosing 'Properties'.

Answer 2

For us, the problem was caused by something else. The license file for the DevExpress components included two lines, one for an old version of the components that was not installed on this particular computer. Removing the older version from the license file solved the issue.

The annoying part is that the error message gave no indication to what reference was causing the problems.

Answer 3

Mine was a very similar situation to the post by Nathan Bedford but with a slight twist. My project too referenced the changed dll in two ways. 1) Directly and 2) Indirectly by referencing a component (class library) that itself had a reference to the changed dll. Now my Visual studio project for the component(2) referenced the correct version of the changed dll. However the version number of the compnent itself was NOT changed. And as a result the install of the new version of the project failed to replace that component on the client machine.

End result: Direct reference (1) and Indirect reference(2) were pointing to different versions of the changed dll at the client machine. On my dev machine it worked fine.

Resolution: Remove application; Delete all the DLLS from application folder; Re-install.Simple as that in my case.

Answer 4

I would like to just add that I was creating a basic ASP.NET MVC 4 project and added DotNetOpenAuth.AspNet via NuGet. This resulted in the same error after I referenced a mismatching DLL file for Microsoft.Web.WebPages.OAuth.

To fix it I did a Update-Package and cleaned the solution for a full rebuild.

That worked for me and is kind of a lazy way, but time is money:-P

Answer 5

I just found another reason why to get this error. I cleaned my GAC from all versions of a specific library and built my project with reference to specific version deployed together with the executable. When I run the project I got this exception searching for a newer version of the library.

The reason was publisher policy. When I uninstalled library's versions from GAC I forgot to uninstall publisher policy assemblies as well so instead of using my locally deployed assembly the assembly loader found publisher policy in GAC which told it to search for a newer version.

Answer 6

In my case, this error occurred while running an ASP.NET application. The solution was to:

1. Delete the obj and bin folders in the project folder

Clean didn't work, rebuild didn't work, all references were fine, but it wasn't writing one of the libraries. After deleting those directories, everything worked perfectly.