A plugin is a software component that runs within Thunderbird that enables certain types of content (such as music or video) to be played or displayed. When a plugin crashes, Thunderbird gives you the option to submit a crash report. After clearing the crash dialog, you can reload the message to view the content. (You may need to restart Thunderbird if the plugin crash also caused Thunderbird to crash.)
A plugin is a piece of software that displays content that Thunderbird is not designed to display, such as video, audio, online games and presentations that are made in binary proprietary formats. Although plugins run within Thunderbird, they are created and distributed by the companies that make those proprietary formats. Some common plugins are Adobe Flash, Apple QuickTime, and Microsoft Silverlight.
How do I see which plugins are installed?
To see which plugins are installed in Thunderbird, select Tools > Add-ons and click Plugins in the left panel.
What is a crash?
A "crash" occurs when a piece of software suddenly and unexpectedly terminates. Sometimes a plugin crashes without affecting the main Thunderbird application, and sometimes the crashed plugin causes Thunderbird to crash along with it. (See Thunderbird Crashes for more information.) As of Thunderbird 4, some plugins load separately from the main Thunderbird application, which means that Thunderbird does not crash when those plugins crash.
When a plugin crashes, you will see a dialog that allows you to submit a crash report to the Thunderbird team:
What is a hang?
A "hang" occurs when a plugin becomes unresponsive. The plugin has not shut down - it just seems to have locked up. Starting in Thunderbird 4, when a plugin stops responding, Thunderbird waits for 45 seconds before shutting it down automatically. Even though this is technically a hang and not a crash, Thunderbird displays the crash report dialog so you can submit information that will help the Thunderbird team diagnose and fix the problem.
What information is included in the Crash Report?
When a crash report is sent to Mozilla, Thunderbird developers use the information to make future versions of Thunderbird less prone to crashing. Crash reports do not include any personally identifying information. They only include technical information, such as:
the content you were viewing that caused the crash
Many problems with plugins can be solved by updating to the latest version of the plugin. The name of the plugin that crashed can be found in the error message. To check for plugin updates, select Tools | Add-ons, click the gear icon in the top right corner and select Check for Updates.