Apple's new system font, "San Francisco", has two versions - "Compact", for display on small screens like the Apple Watch, and a regular version for display on larger screens like macOS devices.

I am looking to replace the system font on my Mac from SF Regular to SF Compact. This is the procedure I'm using: https://www.macissues.com/2014/11/21/how-to-change-the-default-system-font-in-mac-os-x/

Previously, the macOS font files in the /System/Library/Fonts folder included separate .ttf files for each font weight (bold, light, regular, etc.) On High Sierra, however, there is only one .ttf file containing a single font weight (regular). The file is located here: /System/Library/Fonts/SFNSText.ttf. Using Fontforge, I replaced the alphanumeric glyphs of this font with those from the SF Compact file /System/Library/Fonts/SFCompactText-Regular.otf.

After restart, the following happens:

With modified SF Compact font Any interface text that would normally be bold now fails to render.

For reference, with stock system font: With stock system font

So, my question is: How does macOS display generate bold type instances of the system font?

What's interesting to note is that even when I only modify certain characters ("C", "r", "m"), the entire bold string ("Chrome") fails to render. This leads me to believe that the individual glyphs are not the issue, rather, something is being changed during Fontforge export. Fontforge does have a feature which allows for "Multiple Masters" - different weights and widths of a font contained in the same TTF file, but the original Apple-provided SF font (SFNSText.ttf) does not include any "Multiple Masters".

Any help would be greatly appreciated!

Edit: I am aware that there are also Display and Text variants of both fonts (SF and SF Compact). The menu bar uses the Text variant, so I am focusing on that one.

1 Answer 1


If you go to Apple Fonts you can download the SF Pro or SF Compact Fonts. When I download and open the SF Pro I got 30 .otf files for Text and Display fonts. I installed these using Font Book. This installed SF Text and SF Display. SF Text contains 16 variations ranging from Regular to Bold and including Semi-Bold, Heavy Italics, and Text Light among others.

  • 2
    I already have the SF Pro and SF Compact Fonts, and the Display/Text versions for both. What I am looking for is to replace the system UI font, which you cannot do by simply installing fonts using Font Book. The fonts files in the /System/Library/Fonts folder must be edited like so: macissues.com/2014/11/21/… Everything works except places where the system font should be bold (e.g. the name of the active application in the menu bar)
    – user575432
    Commented Aug 12, 2018 at 4:04

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