Could not load file or assembly 'Microsoft.ReportViewer.WebForms'

I am trying to use the report viewer in asp.net and have uploaded my site. However, when my page containing the report viewer is loaded, it shows the following error:

Could not load file or assembly 'Microsoft.ReportViewer.WebForms, Version=11.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

This is my first time deploying an ASP.NET website, so I'm not sure what the problem is.


This link gave me a clue that I didn't install a required update (my problemed concerned version nr, v11.0.0.0)

ReportViewer 2012 Update 'Gotcha' to be aware of

I installed the update SQLServer2008R2SP2

I downloaded ReportViewer.msi, which required to have installed Microsoft® System CLR Types for Microsoft® SQL Server® 2012 (look halfway down the page for installer)

In the GAC was now available WebForms v11.0.0.0 (C:\Windows\assembly\Microsoft.ReportViewer.WebForms v11.0.0.0 as well as Microsoft.ReportViewer.Common v11.0.0.0)


I've installed Microsoft.ReportViewer.2012.Runtime nuget package and problem has been solved without installing ReportViewer.msi or sql feature pack 12

enter image description here


You need to reference both Microsoft.ReportViewer.WebForms and Microsoft.ReportViewer.Common and set the CopyLocal property to true. This will result in the dll's being copied to our bin directory (both are necessary).


I've solved the problem by copying both

  • Microsoft.ReportViewer.WebForms.dll from C:\Program Files (x86)\Microsoft Visual Studio 12.0\ReportViewer
  • and Microsoft.reportviewer.common.dll from C:\Program Files\Microsoft Office\Office15\ADDINS\PowerPivot Excel Add-in

into bin folder (website).

Of course web.config must have:

    <httpHandlers>
        <add path="Reserved.ReportViewerWebControl.axd" verb="*" type="Microsoft.Reporting.WebForms.HttpHandler, Microsoft.ReportViewer.WebForms, Version=11.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91" validate="false" />
    </httpHandlers>

    <assemblies>

        <add assembly="Microsoft.ReportViewer.WebForms, Version=11.0.0.0, Culture=neutral, PublicKeyToken=89845DCD8080CC91" />
        <add assembly="Microsoft.ReportViewer.Common, Version=11.0.0.0, Culture=neutral, PublicKeyToken=89845DCD8080CC91" />
    </assemblies>

    <buildProviders>
        <add extension=".rdlc" type="Microsoft.Reporting.RdlBuildProvider, Microsoft.ReportViewer.WebForms, Version=11.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91" />
    </buildProviders>

    <system.webServer>
        <validation validateIntegratedModeConfiguration="false" />
        <handlers>
            <add name="ReportViewerWebControlHandler" preCondition="integratedMode" verb="*" path="Reserved.ReportViewerWebControl.axd" type="Microsoft.Reporting.WebForms.HttpHandler, Microsoft.ReportViewer.WebForms, Version=11.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91" />
        </handlers>
    </system.webServer>

And that's all. For me is ok.

Hope this helps.