Can't add fonts to Font Book
Running the latest version of Sierra (10.12.5), Font Book 7.0. Just got a new MacBook Pro with Sierra pre-installed.
Font Book won't allow me to add new fonts either by pressing the + key or drag-and-dropping them into the app window. I can turn off unneeded fonts (like the non-English ones), so the app isn't completely frozen.
Has anyone seen anything like this? Can I reinstall the Font Book app? Is there a preference or security feature I'm overlooking that's new to Sierra? Very frustrated.
MacBook Pro (13-inch, 2017, 4 TBT3), macOS Sierra (10.12.5)