Infamous assembly binding error

In my case i got this issue because i was running a web project compiled for x64 using IISExpress. I fixed the issue by checking the following setting in Visual Studio:

Tools | Options | Projects and Solutions | Web Projects | Use the 64 bit version of IIS Express

Hope this helps anyone else with this same scenario and issue

Replaced the 64bit versions of all the three dlls with their 32 bit versions, cleaned Temporary ASP.NET files folder and compiled again. Now works without problems. Thanks for the help.

Try setting Copy Local in solution explorer for those assemblies and make sure they are being dropped into the folder's specified in the binding log.

Also, they were probably built using the V2 CLR. If they were, you'll have to enable Mixed Mode binding by adding this to your web/app config

<configuration>
   <startup  useLegacyV2RuntimeActivationPolicy="true">
       <supportedRuntime version="v4.0"/>
  </startup>
</configuration> 

To solve this, I ensured all my projects used the same version by running the following command and checking the results:

update-package Newtonsoft.Json -reinstall

And, lastly I removed the following from my web.config:

  <dependentAssembly>
    <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0" />
  </dependentAssembly>

I know this is an old question, but still seems to be a popular result when searching for a solution regarding a partial binding error in Visual studio. I had experienced a very similar issue to the original poster, but with the EntityFramework.dll and Visual studio 2015 (.ASP Web Forms project), however, the solution I found relates to a broad problem. Since I didn't find any answers similar to my solution, I thought it might be helpful to contribute what I found, and I hope it does help someone.

In my web.config I am impersonating a domain user that is a service account. This service account did not have access to my Temporary files folder, therefore when debugging, it could not copy the dlls out there, and therefore could not load them.

What finally tipped we off was going and physically looking in the temporary folder mentioned in the error message. In the original question above, you'll notice the lines "Attempting download of new URL file:///C:/Windows/Microsoft.NET/Framework/v4.0.30319/Temporary ASP.NET Files..." When I looked in that folder, my DLLs were not there.

The solution for me was this: Since I was using 64bit environment, and impersonating a domain account, I added the domain service account user to my local C:/Windows/Microsoft.NET/Framework64/v4.0.30319/Temporary ASP.NET Files folder with write (and modify - for good measure) access.

Bottom line - make sure your Temp files folder grants write access to the user your app is running as.

This is an old question, but was still the top result when I had this same issue today. I had switched my project compilation in Visual Studio to target x64 instead of 'All CPUs' (it's on a 64-bit machine). As per the other answers, there would be two ways to fix it - either change everything to 32-bit or everything to 64-bit. In this case, I needed 64-bit.

KabanaSoft's answer worked perfectly for me. Still correct as of Visual Studio 15.6.6.

I was getting the error when trying to run the web application from Visual Studio, but in my case the answer was simple. When I read the exception carefully I could see that the assembly in question was no longer used by the application but a copy was still in the bin folder. After the offending assembly was removed, the error vanished.

In my case I had gone through my site and replaced the name of the site with a new name. I inadvertently replaced the 'PreviousWebSiteName' with the 'NewWebSiteName' in Web.config where the assembly name was being specified.

    <pages enableSessionState="false" enableViewStateMac="true" enableEventValidation="true" controlRenderingCompatibilityVersion="4.0" clientIDMode="AutoID">
  <controls>
    <add assembly="NewWebSiteName" namespace="App_Code.Controls" tagPrefix="blog" />
  </controls>
</pages>

The site was still building an assembly with the old name - I only intended to change the site name where it was appearing on the pages of the site; I didn't need to change anything internally. Restoring the Web.config entry as it was before my naming change (resulting in an entry that matched the name of the built assembly) resolved the error for me.

In my case I had some crap in my web.config, specifically a half-commented out httpHandler that once I cleaned that up, my binding issue disappeared.