I see them in the Quarks folder in Application Support > downloaded-quarks etc…, so where’s the problem? I’ve even tried re-installing SC thinking there might be an error elsewhere, but still no luck! This means that I can’t get to the Quarks.gui to install the quark(s) mentioned. I’ve tried opening SC via s.boot, but nothing happens. Users/admin/Library/Application Support/SuperCollider/downloaded-quarks/ddwMIDI/MIDIRecGUI.sc Users/admin/Library/Application Support/SuperCollider/downloaded-quarks/ddwChucklib/ChuckMIDIGui.scĮRROR: Superclass 'HJHObjectGui' of class 'MIDIRecGUI' is not defined in any file. I’m getting this error message in the post window, the help window doesn’t even open: ERROR: Superclass 'HJHObjectGui' of class 'MTGui' is not defined in any file. After trying to uninstall (to reinstall) ddwGUIEnhancements quark using the Quarks.gui, SC just won’t open (completely) and remains blocked trying to compile the library.