Open a previously created MuseScore file. It won't open in MuseScore 4 (even if created by MuseScore 4). Instead, the Window for previous files opens up. If the file being opened is deep in some folder, then I have to go looking for it to place it on the desktop (my easiest way) to open it directly using the MuseScore 4 menu path. This must be a Bug.
|She's Not There.mscz