■
In this case, don't force the application (or X11) to quit; wait for the Fonts Cache to rebuild.
If an application doesn't open anymore or seems blocked on a message displaying "Caching Fonts", you have probably removed the Fonts Cache.
In this case, don't force the application (or X11) to quit; wait for the Fonts Cache to rebuild.
Indeed, the rebuilding of Fonts Cache in some Open Source applications (GIMP, MPlayer OSX Extended, and so on) is particularly long.
After the Cache is rebuilt, the application will open again normally.