Identify Missing System Font After installing Sierra and a number of other fonts from Google Web Fonts, I now see the 'question mark' against any list items either within the actual system UI and other applications such as Chrome.




Edit:
I have already attemped two possible solutions:


Font Book for Mac: Restore standard fonts
How to Restore Default Fonts on Mac
Run sudo atsutil databases -remove, then reboot.

atsutil is the CLI for the font registration system. Resetting the database can help clear up errors like this. Also see Check mark disappeared from dropdowns.