Could not load file or assembly 'DocumentFormat.OpenXml

Question

I'm keep getting this error is VS2013

Could not load file or assembly 'DocumentFormat.OpenXml, Version=2.0.5022.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies.

In my web.config

    <?xml version="1.0"?>
<!--
  For more information on how to configure your ASP.NET application, please visit
  http://go.microsoft.com/fwlink/?LinkId=169433
  -->
<configuration>
    <connectionStrings>
        <add name="hjkom_med_web_udvConnectionString" connectionString="Data Source=M95;Initial Catalog=hjkom-med_web;Persist Security Info=True;User ID=HJkom-MED_web;Password=bvkeB7hh" providerName="System.Data.SqlClient"/>
    </connectionStrings>
    <system.web>
        <compilation debug="true" targetFramework="4.0">
            <assemblies>
                <add assembly="System.Data.Linq, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/>
                <add assembly="WindowsBase, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
                **<add assembly="DocumentFormat.OpenXml, Version=2.0.5022.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>**

</assemblies></compilation>
    </system.web>
</configuration>

I have tried to insert windowsbase and a lot of other things.

I have search and search for a solution, do any body know how to fix it?

Answer 1

I had this problem because I had a new version of the .dll installed on my computer running on localhost and my server was running an old version of the same .dll

I just updated it and everything works well after that.

In your case, install the DocumentFormat.OpenXml version 2.5 available in this microsoft link

Answer 2

At the time of writing this answer, there are 3 versions of Open XML SDK:

• Open XML SDK 1.0 (NuGet link)
• Open XML SDK 2.0 (NuGet link)
• Open XML SDK 2.5 (NuGet link)

You most probably have referenced in your project DLL version 2.5 which was installed on your machine.
To get required v2.0 assembly, I suggest you to use NuGet I provided above.