How to Validate Fonts for Corruption in macOS 13

Corrupted or poorly formatted fonts can lead to application crashes, system instability, and visual rendering errors across macOS 13 Ventura. This guide outlines how to use the built-in macOS Font Book utility to quickly scan, identify, and resolve issues with damaged fonts installed on your system.

How to Scan and Validate Installed Fonts

  1. Open Font Book Press Command + Space to launch Spotlight, type Font Book, and press Return. Alternatively, open Finder, navigate to the Applications folder, and double-click Font Book.

  2. Select the Fonts to Test

    • In the left sidebar, click All Fonts to test the entire system library.
    • Click any font in the list, then press Command + A on your keyboard to select every installed font.
    • Alternatively, select individual fonts or specific font families by holding Command and clicking them individually.

  3. Run the Validation Tool

    • Go to the menu bar at the top of the screen and click File.
    • Select Validate Selection (or Validate Font if only one is selected).

  4. Review the Results A "Font Validation" window will appear displaying the scan progress and categorizing the results by status:

    • Green Checkmark (Passed): The font is healthy, safe to use, and has no detected errors.
    • Yellow Warning Icon (Caution): The font has minor structural warnings or duplicates. These are usually non-fatal, but duplicate fonts can cause rendering conflicts.
    • Red 'X' Icon (Failed): The font is damaged, incomplete, or corrupted. These fonts frequently cause system crashes and should be removed.

How to Fix or Remove Problematic Fonts

  1. In the Font Validation results window, use the drop-down filter at the top to display Warnings or Errors only.
  2. Check the box next to any font displaying a red 'X' or an unresolved yellow warning.
  3. Click the Remove Selected button at the bottom of the window to uninstall the corrupted font files from your Mac.
  4. If prompted, enter your macOS administrator password to confirm the deletion.

Resolving Remaining Font Glitches

If you continue to experience text rendering bugs after removing corrupt fonts, restart your Mac in Safe Mode (hold the Power button on Apple Silicon Macs, or hold Shift during startup on Intel Macs). Booting into Safe Mode automatically clears the system font caches and rebuilds the font registry, eliminating residual display artifacts. Restart normally afterward.