Resolving the “Could not load type 'System.ServiceModel.Activation.HttpModule'“ error when running the ASP.NET or ASP.NET MVC sample browser

This issue may arise if you have installed Syncfusion Essential Studio with all the product components including Silverlight in the IIS-configured machine. This is a known issue, and it will be fixed starting from version 11.x.x.xx of Syncfusion Essential Studio.

As a workaround, you can resolve it by running Aspnet_regiis.exe with the below arguments to re-register the correct version of ASP.NET in the IIS web server.

1. Open the command prompt with administrative privileges and navigate to the the Aspnet_regiis.exe file, which can be found in one of the following locations:

• %windir%\Microsoft.NET\Framework\v4.0.30319
• %windir%\Microsoft.NET\Framework64\v4.0.30319 (on a 64-bit computer)

2. Run Aspnet_regiis.exe with the following arguments: aspnet_regiis.exe /iru

3. Refresh the IIS web server or run the iisreset command in admin mode and restart the Syncfusion dashboard.