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

The .NET Assembly loader:

• is unable to find 1.2.0.203
• but did find a 1.2.0.200

This assembly does not match what was requested and therefore you get this error.

In simple words, it can’t find the assembly that was referenced. Make sure it can find the right assembly by putting it in the GAC or in the application path.

run below command to add the assembly dll file to GAC:

gacutil /i "path/to/my.dll" 

Also see https://learn.microsoft.com/archive/blogs/junfeng/the-located-assemblys-manifest-definition-with-name-xxx-dll-does-not-match-the-assembly-reference.