I've installed a font in the font book, but the bold format does not work. I see the bold in the font book. Also, the italic format does work. How to fix it? (I'm running on El Capitan).

Is there an option to reinstall the font?

2 Answers 2


Your font could be broken. Not likely if it worked before but at least it is easy to check as there’s a font validator built into Font Book. Please mark the font and select File > Validate Font.

If you receive warnings or errors there’s no built in repair tool, though. But then at least you know...

  • Also note that some applications allow you to apply bolding to a font (select word and tap command B) while others require that you select the bold version of the font from the font menu, essentially picking a different font. Aug 31, 2017 at 13:34
  • @Tom E thanks for the tip. I get that all is ok with the font. Do you have another idea? Aug 31, 2017 at 18:17
  • You could do a safe boot—press the shift key upon restart. Among other things this will clear the font cache. Please note that safe boot is for maintenance only so restart your Mac immediately into regular boot once safe boot has finished.
    – Tom E
    Sep 1, 2017 at 6:48
  • @TomE I did a normal restart and it didn't help. Is this safe boot different? Is there an option to clear the font cache without a restart? Sep 1, 2017 at 9:21
  • @roi.holtzman: A normal restart doesn’t clean the font caches. And a reboot doesn’t cost much—it’s one small step for the Mac yet a giant leap for your usage ;-)
    – Tom E
    Sep 1, 2017 at 11:11

So at the end, it got very simple. I just recopied the fonts to the Font Book and let it fix itself automatically, and it solved the issue! The Bold mode is working again!

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