Troubleshooting Silverlight on a Mac - up to Safari 11

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Windows users should visit for Silverlight issues.

Users who are running a Macintosh computer running Safari version 12, please go here:

TestOut/LabSim products built before 2015 relied on Microsoft Silverlight, an extension which is no longer supported by some browsers. The only supported browsers for both Microsoft Silverlight and these courses are Internet Explorer 11 and Safari 8+ (as of January 2017).



If you get any error specifically mentioning Silverlight while working within LabSim it may be due to any of the following reasons.

  • Microsoft Silverlight is not installed on your computer.
  • The Microsoft Silverlight install on your computer is corrupt. 
  • Microsoft Silverlight has been disabled within your browser. 


Microsoft Silverlight is a LabSim system requirement for TestOut Client Pro, Windows Server Pro for (70-410, 70-411, 70-412), Configuring Windows 7, Windows Server 2008 for (70-640, 70-642, 70-643, 70-646, 70-647), and some of our older courses.  Silverlight needs to be installed on your computer prior to launching the a lab simulation in one of these LabSim Products.

Installing Microsoft Silverlight on a Mac

  • Locating Silverlight on Microsoft’s website
  • Verifying your system requirements
    • Make sure you are running a Silverlight-compatible operating system and browser and that you have uninstalled any previous version of Silverlight.
  • Download Silverlight
    • Click the ‘Click to Install’ link – the Silverlight.dmg file will download to your Downloads folder
    • From within the Downloads folder, double-click Silverlight.dmg. This will extract the Silverlight.pkg file into the Silverlight folder.
  • Installing Silverlight
    • From within the open Silverlight folder double-click Silverlight.pkg
    • The install package will first want run a program to determine if the Silverlight Browser Plug-In software can be installed. You will click Continue to run this program
    • Assuming the program determines that Silverlight can be installed within your operating system and browser you will be prompted to click Continue to begin the installation
    • Click Continue, and the Agree to accept the license
    • Click Install to begin the installation. You are also provided the option to Change Installation Location if desired. The install will take approximately 102 MB of space on your computer
    • At this point you should be prompted to enter your system password and click Install Software
    • After the successful installation you can click the Close button to close the installation program
    • After installing Silverlight, close Safari completely before logging back into TestOut to try loading the lab again.

Uninstalling corrupt a Silverlight plugin on Mac

  • Should Silverlight become corrupted or otherwise stop working, uninstalling and then reinstalling may resolve the issuel. To uninstall Microsoft Silverlight on a Mac, simply click on the Spotlight search icon in the top right corner of the screen, type Silverlight.plugin, select it from the list and drag it to the trash. (as shown in the screenshot below)

  • After reinstalling, close Safari completely before logging back into TestOut to try loading the lab again.

Ensuring that Silverlight is enabled within Safari.

Compare steps 1-5 to the first image below.

  1. Click the Safari menu
  2. Click Preferences
  3. Click on the Security tab
  4. Ensure that a check is next to Allow Plug-ins.
  5. Click Plug-in Settings

Compare the second set of steps to the second image below.

  1. Ensure that a check is next to Silverlight
  2. Click on Silverlight
  3. Turn On the plugin for all websites, especially,
  4. Click Done.

Completely close and then restart Safari before logging in to try the labs again.

If issues persist, or if additional information is needed, please contact Technical Support via any of the below options:
Telephone: 800-877-4889, Option 2
Live Chat: See link upper right at