Font is installed in font book, but bold does not work

Question

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?

Answer 1

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!

Answer 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...