[Firefox Tip] Enable Support for NPAPI Plugins Such as Silverlight, Java, Acrobat, etc

In the recently released Mozilla Firefox 52 version, Mozilla has disabled support for NPAPI (Netscape Plugin Application Programming Interface) plugins such as Microsoft Silverlight, Java, Unity, Acrobat, Shockwave, DivX, etc. Only support for Adobe Flash Player plugin is enabled as its still widely used by websites.

Mozilla decided to disable supports for all NPAPI plugins except Adobe Flash as according to the company, these plugins are the main reason behind browser crashes and other performance and security related issues.

The good news is that if some users want to enable support for all NPAPI plugins back in Firefox browser, Mozilla has provided a preference to turn on the support in the meantime.

If you also want to bring back support for all NPAPI plugins in Mozilla Firefox 52 or later versions, this tutorial will help you.

We'll need to use Firefox advanced configuration tool "about:config" to re-enable support for NPAPI plugins as shown in following steps:

1. Open Mozilla Firefox and type about:config in the addressbar and press Enter. It'll show you a warning message, click on "I accept the risk!" button. It'll launch Firefox's hidden advanced configuration page.

2. Now right-click anywhere in the preferences list and select "New -> Boolean" option.


3. Type plugin.load_flash_only in the preference name box and click on OK button.


4. Now select False in the boolean value box and click on OK button.


That's it. Restart Firefox and now all disabled NPAPI plugins should start working again without any problem.

NOTE: According to Mozilla, this built-in preference to bring back support for NPAPI plugins might be removed completely in future Firefox versions.


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Posted in: Mozilla Firefox

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  • Thanks, my silverlight works.

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