I swear I've installed Silverlight at least 10 times on my Mac. I've got firefox 15 installed . I can use silverlight on my other browsers but not firefox. I called Netflix and they say they have no idea. This also happens on other sites besides netflix.
Every time I visit a site that uses Silverlight, I am prompted to download and install it again.
I had this same problem, netflix wouldn't play on firefox but would play on Safari. I followed the instructions above and notice that Silverlight was never automatically enabled. So I enabled Silverlight and now Netflix works!! Yay!!
Thank you Tylerdowner!!
fix Firefox and Silverlight by doing the following:
1) Make sure you can see your Mac's hard drive (HD) by following these instructions:
In the Finder, choose Preferences from the Finder menu.
Click the General icon on the toolbar.
Select "Hard disks" in the "Show these items on the desktop:" section.
Close the Finder Preferences window.
2) Ok, now you can see your hard drive. You need to fully remove SilverLight and then install it from Microsoft directly.
3) Access your hard drive
Double-click the hard drive icon on your desktop
Find the plugin
Navigate to your Internet Plug-Ins directory: /Library/Internet Plug-Ins/
Remove the plugin
Drag any of the following into your trash bin:
To find out how to uninstall the following plug-ins, visit the Removing Silverlight Controls on Macintosh page: