HRESULT: 0x80131040: The located assembly's manifest definition does not match the assembly reference

This is a mismatch between assemblies: a DLL referenced from an assembly doesn't have a method signature that's expected.

Clean the solution, rebuild everything, and try again.

Also, be careful if this is a reference to something that's in the GAC; it could be that something somewhere is pointing to an incorrect version. Make sure (through the Properties of each reference) that the correct version is chosen or that Specific Version is set false.

Just delete the bin folder and then then the project recreates all again and it will be working now .

I ran into similar problems when accessing the project files from different computers via a shared folder. In my case clean + reabuild did not help. Had to delete the bin and objects folders from the output directory.

In my case I got this message while debugging:

"Error while calling service <ServiceName> Could not load file or assembly 'RestSharp, 
Version=105.2.3.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. 
The located assembly's manifest definition does not match the assembly reference.
(Exception from HRESULT: 0x80131040)"

Cause

In my project I have had 2 internal components using the RestSharp but both component have different version of RestSharp (one with version 105.2.3.0 and the other with version 106.2.1.0).

Solution

Either upgrade one of the components to newer or downgrade the other. In my case it was safer for me to downgrade from 106.2.1.0 to 105.2.3.0 and than update the component in NuGet package manager. So both components has the same version.

Rebuild and it worked with out problems.

Just Check your webconfig file and remove this code :-

<dependentAssembly>
    <assemblyIdentity name="itextsharp" publicKeyToken="8354ae6d2174ddca" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-5.5.13.0" newVersion="5.5.13.0" />
  </dependentAssembly>

I got this error when working in the Designer. I had been developing in VS 2012, but "upgraded" to 2017 over the past couple days. Solution was to close and reopen VS.

It may be related to a bug which I've seen reported elsewhere, where the Reference Manager does not work? In that situation, the following error message is encountered when trying to add a reference in the Solution Explorer:

"Error HRESULT E_FAIL has been returned from a call to a COM component."

My workaround was to close the solution, reopen in VS2012, add the reference, close 2012 and reopen 2017. Ridiculous that 2017 should have been released with such an obvious bug.

My WPF project referenced 3 custom dlls. I updated one of them, deleted the reference and added the reference to the new dll. It also showed the correct version number in the properties of the reference. It was rebuilding without an error.

But when the application was running, the failure "The located assembly's manifest .." occured, mentioning the old version.

After searching for a solution for hours and reading couple of threads like this, I remembered the other dlls. One of the other dlls was referencing the old version, and that's why the failure occured. After rebuilding the 2nd dll and recreating both references in my WPF project, the failure was gone.

Don't forget to check your other dlls!

I tested All the solutions above but didn't work out for me, after consideration all situations found out the problem is somewhere else, it was so awkward.
I have two different branches for the same project on different folders, the problem was from the other branch.
I updated nuget packages (for the mentioned package on error page) on both branches and the problem solved!

For me the problem was in the app file version, it was 3.3.1 and i was building the new one as 20.0.1, when reset the version back to the same value it worked fine.