How to debug Firefox problems

This page explains information that should be included when filing bugs related to Firefox. Problems involving Firefox should be filed against firefox.

• Is the bug being triggered by an add-on or is it in Firefox itself? Likely if other testers are not seeing the same problem, or if the bug is associated with file types typically handled by plugins (e.g. Flash, PDFs, RealAudio, QuickTime).
  • Go to "Tools -> Add-ons" in the Firefox menu to see what you have installed. To experiment, you can disable Plugins, Extensions, etc. one by one. You may need to restart the browser for changes to take effect.
  • You can run "firefox -safe-mode" to get the application started without any Extensions or Themes. (Plugins are still loaded.)
  • At the very least, reporting what Plugins and Extensions you have installed is a useful part of a Firefox bug report.
• Is the bug being triggered by some other customization you made? Likely if other testers are not seeing the same problem.
  • Try running Firefox as a different Unix user, who has never run Firefox before.
  • If this solves the problem, it will probably be necessary to find the specific customization (or set of customizations) which triggers the bug.

For crashes, see the Firefox section of StackTraces.