I see no problem in having invalid font dirs in class var. The paths just need to be checked when image starts. why this a problem? If going this way, you can just put there all well known paths for every known platform at package installation phase and don't care if they all valid. Rendering engine must be aware that some or all of given directories can be missing or contain no fonts. You need to check it anyways because they external to image and if i added new directory and then moved/renamed it in my OS the squeak must not crash after restart.