Please check if all your plugins are up-to-date. To do this, go to the Mozilla Plugin Check site.

Once you're there, the site will check if all your plugins have the latest versions. If you see plugins in the list that have a yellow Update button or a red Update now button, please update these immediately.

To do so, please click each red or yellow button. Then you should see a site that allows you to download the latest version. Double-click the downloaded file to start the installation and follow the steps mentioned in the installation procedure.

Does this fix your problem?

I did as ComputerWhiz requested. There was one plugin that needed updating: Shockwave for Director. I updated that plugin and restarted Firefox. The behavior is still the same, i.e. the Java applet will not start or run. I have performed all the steps for correcting Java problems in the Java FAQ and troubleshooting pages. The Java applet runs fine in IE 11 desktop mode after the User Account Control popup is OK ed.

Try Firefox Safe Mode to see if the problem goes away. Safe Mode is a troubleshooting mode, which disables most add-ons.

(If you're not using it, switch to the Default theme.)

• Open the Help menu and click on the Restart with Add-ons Disabled... menu item while Firefox is running.

Once you get the pop-up, just select "'Start in Safe Mode"

If the issue is not present in Firefox Safe Mode, your problem is probably caused by an extension.

To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before opening Firefox for normal use again.

Please report back with your results.

Do you have 32 bit Java installed?

The Java plugin shows in the System Details List.

Do you get a Java security pop-up or at least does Java startup?

Did you check the settings in the Java Control panel?

See also:

• http://kb.mozillazine.org/Java

The answer to both responses above are:

The problem still exists in Safe Mode.

Java 7-25 (32) is installed and configured properly.

The Java security pop-up does not appear.

If the problem still occurs in Firefox Safe Mode, then the issue is not related to or caused by Firefox.

It is either an issue with Windows or your current version of Java.

Try updating Firefox to its most recent version (Firefox 23.0).

Hello, I've presented this problem. There are no pop-ups that say my java plugin is not installed or anything like that. My plug-in is marked as always active but the applets doesnt work. I have windows 8.1 and java SE 7 U47. Also I cannot use internet explorer for the same reason.