Some text shows up bold after upgrade

This article is no longer maintained, so its content might be out of date.

Words on websites could become bold or italic if your font is corrupt or a setting is changed.

Font settings

To verify your settings are correct:

  1. Click the menu button New Fx Menu Fx57Menu and select Options.Preferences.
  2. Select the Content panel.
  3. Under Fonts and Colors, click Advanced....
  4. The default settings are:


    • Fonts for: Western
    • Proportional: Serif
    • Size: 16
    • Serif: Times New RomanTimesSerif
    • Sans-serif: ArialHelveticaSans-serif
    • Monospace: Courier NewCourierMonospace
    • Size: 13
    • Minimum font size: None
    • Default Character Encoding: Western (ISO-8859-1)


Sometimes an extension causes this problem. To check, see Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems.

Corrupt or Missing Fonts

To make sure that your fonts are not corrupt or missing:

  1. Click the Firefox menu Fx57Menu and select Exit.Click the Firefox menu at the top of the screen and select Quit Firefox.Click the Firefox menu Fx57Menu and select Quit.
  2. Open the run dialog.
    • (7/Vista): Click the Windows Start button. The Start Search box is the run dialog.
    • (XP): Click the Windows Start button, then select Run....
  1. Type %WINDIR% and press Enter.
  2. Open the folder called Fonts.
  3. Verify that you have these fonts:
      • Arial.ttf
      • Arial Black.ttf
      • Arial Bold.ttf
      • Arial Italic.ttf
      • Arial Bold Italic.ttf
      • Times New Roman.ttf
      • Times New Roman Bold.ttf
      • Times New Roman Italic.ttf
      • Times New Roman Bold Italic.ttf
      • Courier New.ttf
      • Courier New Bold.ttf
      • Courier New Italic.ttf
      • Courier New Bold Italic.ttf

If you have a font that is a different name, rename it to be the right name. Examples:

  • Arial2.ttf instead of Arial.ttf
  • Arrial.ttf instead of Arial.tff

These fine people helped write this article:

Illustration of hands


Grow and share your expertise with others. Answer questions and improve our knowledge base.

Learn More