If you experience a problem in Firefox after installing a theme, you can launch Firefox in a special Safe Mode that temporarily disables the current theme and resorts to the default. Safe Mode also disables your current extensions (see Chapter 20 for more information about extensions). If the problem isn't present in Safe Mode, either your theme or one of your extensions is causing it. Try disabling the theme or your extensions one by one (from the Theme Manager and the Extension Manager, respectively) until the problem disappears.
To open Firefox in Safe Mode in Windows, shut down Firefox if it is currently open, and then choose Start Programs Mozilla Firefox Mozilla Firefox (Safe Mode).
To open Firefox in Safe Mode on a Mac, you need to enter a special command into the Macintosh Terminal. First, open the Terminal from Applications Utilities Terminal. Then type the following and press Enter:
If you installed Firefox to a different location, you need to modify the path accordingly.