• You are launching FontLab Studio 5.1.x for Mac, for the first time after installing
  • You are on a localized (non-English) version of macOS
  • The app crashes (freezes) on launch


  1. Open the Language & Region control panel in System Preferences and make English your primary language. NOTE: You don't need to restart the system or even close Preferences. 
  2. Run FontLab Studio 5 and activate it.
  3. You can now switch back to your preferred language.

Note also:

Fontlab selects which language to display the user interface based on your system preferences. 

There is also workaround to force FontLab to work in a different language regardless of your language preferences: open the application package, and delete the folders for the languages that are higher in your prefs list than the one you want FontLab to use. The folders have names such as “Spanish.lproj”.