Silverlight: How to remove Mac OS X Mavericks Safari 6.1 sandbox restrictions for Silverlight enabled websites

By default, Mac OS X Mavericks / Safari 6.1 and later now load plugins like PDFs, Flash, Silverlight, and Java in a sandbox to protect users from possible exploits in the plugins, but can also prevent those sites from working as designed.

See "Added security for plug-ins" On
"PDFs and widely used plug-ins like Adobe Flash Player, Silverlight, QuickTime, and Oracle Java are sandboxed in Safari, which protects your system from harm should those plug-ins be exploited. For added security, you can even choose to run only certain plug-ins on trusted websites you select."

For Silverlight enabled sites that do any of the following you may find the sites does not work as expected.
Out-Of-Browser installation
Saving Files to the local machine
Media Playback, like Netflix

To workaround the problem you can allow Silverlight to run outside the sandbox for the sites you trust.

1.  Open Safari to the Silverlight enabled website.

2.  Open Safari->Preferences (⌘,). 

3.  Select the “Security” tab
4.  Make sure “Allow Plug-ins” checkbox is checked
5.  Click the “Manage Website Settings…” button

6.  Select "Silverlight" in the plug-in list on the left
7.  Click the pull-down for the Silverlight enabled website and choose "Run in Unsafe Mode"

8.  In the Alert, click "Trust"

9.  Click the "Done" button
10.  Close the "Preferences" panel
11.  Reload the page




Comments (4)
  1. Bob says:

    Is there going to be a better way to handle this? It seems that Adobe has released a flash update that at least allows the user to be prompted to trust the app. Having the app just fail is a horrible customer experience. Or is this the final nail in the Silverlight coffin?

  2. Gord P. says:

    Thank you, this worked perfectly for me.

  3. Brad Kynoch says:

    I tried exactly as described but this didn't work. Safari still shows "Plugin failure" when I try playing a Netflix movie.

  4. Stephen Cox says:

    This does not work. How about FIXING the plugin?

Comments are closed.

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