Install Silverlight Prompt With Silverlight Already Installed

In some versions of Internet Explorer, sites that use Silverlight may display the “Install Silverlight” graphic in lieu of the expected content, even though the latest version of the Silverlight runtime is already installed on the client. For example, a Silverlight Web Part displaying this behavior is shown below. Silverlight is installed on this client.

Install Silverlight prompt in a Silverlight Web Part

This can be caused by the security setting “ActiveX Filtering” being enabled. It’s probably best to leave this setting enabled in the browser, and instead selectively disable it for certain sites. In IE9 (and IE 10 also?), it is possible to do this right from the browser navigation box by clicking the filtered content icon and turning off filtering for the selected site, as shown below.

Disabling ActiveX Filtering for a site

If this is the cause of your problem, changing the setting will reload the page and load the Silverlight content.

Another option would be to add the site to “Trusted Sites”, and verify that the Trusted Sites group has the setting disabled.