I installed Microsoft's KB2393802 and my Java plugin for Firefox 3.6.13 no longer works. Java still works fine in IE. I uninstall KB2393802 and it works fine in both. I am running the latest version of Java (Version 6 update 24 (build 1.6.0_24-b07)). I verified in the Advanced tab that both "Default Java for Browsers - Mozilla Family" and Java Plug-in "Enable next-generation java plug-in" are checked. Under Firefox Add-ons/extensions, the only version of Java Console is 6.0.24 and it is enabled. Under Plug-ins, Java Platform SE 6 U24 6.0.240.7 is enabled. I have 4 different machines all running similar software but on different hardware. Some of the plugins may differ. This is only machine that has a problem. I have tried uninstalling Java and Firefox (using Revo uninstaller) and reinstalling both. Problem still exists.