The Microsoft Silverlight add-on is listed as not verified in Microsoft Internet Explorer

Important

The Internet Explorer 11 desktop application will be retired and go out of support on June 15, 2022 (for a list of what's in scope, see the FAQ). The same IE11 apps and sites you use today can open in Microsoft Edge with Internet Explorer mode. Learn more here.

Original product version:   Internet Explorer
Original KB number:   2406108

Symptoms

You install Microsoft Silverlight in Internet Explorer. Next, you open the Manage Add-ons feature in Internet Explorer and view the Silverlight add-on information. The publisher is listed as (Not verified) Microsoft Corporation.

Cause

This behavior occurs because while the installation package of Microsoft Silverlight is digitally signed, the add-on file npctrl.dll isn't digitally signed. Internet Explorer checks the digital signature of the control's binary file when it determines the publisher. If the signature is missing, the publisher information will be listed as Not verified.

Resolution

This is a behavior by design.

More information

The installation package of Microsoft Silverlight is digitally signed. This ensures the add-on is installed from an identified resource. For more information, see Manage add-ons in Internet Explorer 11.