The first step is to uninstall any previous Silverlight Runtime you may have and install Silverlight Developer Runtime version 5.1.50918.0 which you can find here:

• Silverlight for Win 64bit
• Silverlight for Win 32bit

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Note:

Silverlight automation only works with the Developer Runtime version installed.

To automate windowless Silverlight applications you need to activate the UiPath Extension for Silverlight. The simplest way to install the bridge extension is accessing the Tools page from the Studio Backstage View and clicking the Silverlight Extension button.

You can also install the UiPath Extension for Silverlight by using a command prompt opened with administrator rights, and running one of the following commands:

• C:\Program Files (x86)\UiPath Studio\v8\UiPath\SetupExtensions.exe /silverlight
• C:\Program Files (x86)\UiPath Studio\v8\UiPath\slinject.exe /install - This command displays more info in the console.
• C:\Program Files (x86)\UiPath Studio\v8\UiPath\slinject.exe /uninstall - This command uninstalls the extension. This also removes any extension entries in the Control Panel Add/Remove Programs section.

Note that in all cases administrator rights are required. If UAC is disabled SetupExtensions.exe might fail silently (at least in older versions of Studio).

Windows auto-update can silently update the Silverlight runtime. It is recommended to clear the Enable Microsoft Update option in the last step of the Silverlight installer wizard or configure Silverlight updates using:

C:\Program Files (x86)\Microsoft Silverlight\5.1.50918.0\Silverlight.Configuration.exe

You can check the windowless parameter using the UiExplorer tool as follows:

• Search for the <param name=”windowless” /> tag under the corresponding <object /> element.
• Use the DOM Explorer in Internet Explorer (press F12 to open it).