Musescore 4 doesn't open any more
I have installed musescore 4 on a MACOS system, with success, and used it for one week. But it does not open anymore, just see the window "Muscore loading", then disappear. I also tried to launch it directly clicking on a partition, but doesn't work neither. I have seen a post on such a problem on Musescore 3, saying to reset the initial parameters, but I don't know how to it here.
Furthermore, I can not open my files opened and save on 4, on musescore 3
Thanks for helping
There has been an update to Muse Sounds that prevents older (i.e. before 3 Dec) versions of MU4 opening. See https://github.com/musescore/MuseScore/issues/14907
Assuming your Muse sounds have been updated you also need to update to the latest nightly version of MU4. If that doesn't work you should report the problem on Github as described in the MU4 beta release announcement.
Version 4 files indeed cannot be opened in version 3. That has always been the case. Version 4 is still undergoing development and the available versions are intended to be used only for testing purposes to uncover the remaining bugs. It should not be used for "real" work, or at least if it is used it is at your risk. There is no guarantee that scores produced now in the latest version of MU 4 will be compatible with later development versions.
Having given those warnings, all is not lost if all you have is a MU4 version of a score. You should be able to export it as a musicxml and import that to MU 3 with little loss of content or formatting.
In reply to There has been an update to… by SteveBlower
Thanks for this fast answer, it does work again.