Could not load file or assembly Microsoft.ReportViewer.WebForms

Date Published: 24 January 2007

Could not load file or assembly Microsoft.ReportViewer.WebForms

Ran into this error while deploying an application to production:

Configuration Error

Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.

Parser Error Message: Could not load file or assembly โ€˜Microsoft.ReportViewer.WebForms, Version=, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3aโ€™ or one of its dependencies. The system cannot find the file specified.

A quick search found the issue. The server needs these three files:


These get installed by ReportViewer.exe, which can be found here:

C:Program FilesMicrosoft Visual Studio 8SDKv2.0BootStrapperPackagesReportViewerReportViewer.exe

In my case I just FTPโ€™s up my entire C:Program FilesMicrosoft Visual Studio 8SDKv2.0BootStrapperPackagesReportViewerfolder to the server and then I was able to run the EXE without problem.

Steve Smith

About Ardalis

Software Architect

Steve is an experienced software architect and trainer, focusing on code quality and Domain-Driven Design with .NET.