Behavior:
A new stable version of the popular Firefox browser was released today. This is the first version of the browser which has support for classic NPAPI plugins disabled.
Solution:
In Firefox 52, the user can turn on NPAPI plugin support using about:config.
Here is how it can be done.
- Open a new tab in Firefox and enter the following text in the address bar: about:config
Confirm that you will be careful if a warning message appears for you.
- Create a new boolean option and name it 'plugin.load_flash_only.'
- Set the plugin.load_flash_only option to 'false'.
- Restart Firefox.
Other links:
Google Chrome V42 disables Silverlight : KBA-35408