Could not load file or assembly System.Web.Http.WebHost after published to Azure web site

Question

The dll is missing in the published (deployed environment). That is the reason why it is working in the local i.e. Visual Studio but not in the Azure Website Environment.

Just do Copy Local = true in the properties for the assembly(System.Web.Http.WebHost) and then do a redeploy, it should work fine.

If you get the similar error i.e. some other assembly missing, then make that assembly to copylocal=true and redeploy, repeat this iteratively - if you are unsure of its dependencies.

If you are still looking for an answer, try checking this question thread. It helped me resolve a similar problem.

edit: The solution that helped me was to run Update-Package Microsoft.AspNet.WebApi -reinstall from the NugGet package manager, as suggested by Pathoschild. I then had to delete my .suo file and restart VS, as suggested by Sergey Osypchuk in this thread.

I met the same problem and I resolved it by setting CopyLocal to true for the following libs:

System.Web.Http.dll
System.Web.Http.WebHost.dll
System.Net.Http.Formatting.dll

I must add that I use MVC4 and NET 4

For me worked adding the following section to web.config file:

<configuration>
...
    <runtime>
    ...
        <dependentAssembly>
            <assemblyIdentity name="System.Web.Http.WebHost" publicKeyToken="31bf3856ad364e35" culture="neutral" />
            <bindingRedirect oldVersion="0.0.0.0-5.1.0.0" newVersion="5.1.0.0" />
        </dependentAssembly>
    ...
    </runtime>
...
</configuration>

This example stands for MVC 5.1. Hope it will help someone to resolve such issue.

For me it started working after selecting "Remove additional files at destination" in File publish options under settings on the publish dialog.

The dll is missing in the published (deployed environment). That is the reason why it is working in the local i.e. Visual Studio but not in the Azure Website Environment.

Just do Copy Local = true in the properties for the assembly(System.Web.Http.WebHost) and then do a redeploy, it should work fine.

I'm using vs2012 and i think the update KB2781514 changed some setting. All my System.Web.Http in my MVC4 project changed to false and i keeping received this message. I had changed the All file in this project in publish property but its not working. Finally I have to change Copy Local = true one by one and solved this problem.