Resolve Automatically: Font Book deactivates duplicates or moves them to the Trash, depending on the option selected in Font Book settings. In the Font Book app on your Mac, choose File > Resolve Duplicates. You can also check for duplicate fonts manually. You can choose whether to keep both versions, skip font installation, or replace the existing font with the new font. Font Book automatically checks for duplicates when you install a font, and shows a message if the font is already installed.
