Solution for ASP.NET Error: Could not load file or assembly ‘System.Web.Extensions’

The Main reason for this error is ‘Your Application uses Microsoft ASP.NET 2.0 AJAX Extensions 1.0 and they had not been installed on your hosting server’

Solution – 1

  1. Download the ‘ASPAJAXExtSetup.msi‘ installer from Microsoft and run it on the live server. The required .dll files would then be inserted into the GAC

Solution – 2

  1.  Your Server did not exhibit the problem, so server obviously had the dll files. Then The Simple Answer is to place a copy of these following files in the applicatiion’s ‘Bin’ folder
    1. System.Web.Extensions.Design.dll
    2. System.Web.Extensions.dll

    You can find these files at C:\Program Files\Microsoft ASP.NET\ASP.NET 2.0 AJAX Extensions\v1.0.61025\


6 thoughts on “Solution for ASP.NET Error: Could not load file or assembly ‘System.Web.Extensions’

  1. I have installed ASP.NET 3.5, Visual Studio 2008 and the current Ajax release and get the same error.

    Does this mean I need to install ASP.NET 2.0 to use these controls ?

  2. .NET 3.5 has ASP.NET AJAX built-in, Visual Studio 2008 and Visual Web Developer 2008 also now have great support for integrating JavaScript and AJAX into your applications

  3. i have added the assembly file but not able solve the problems. again i am getting “could not load assembly or any one of defendency not there”

    plz get me the solution

    thanks & regards


  4. Visual Studio .NET has detected that the specified Web server is not runing ASP.NET version 1.1 Yuu will be unable to run ASP.NET Web applications or services.

Leave a Reply

Please log in using one of these methods to post your comment: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s