Cannot save existing .mscz file on Macosx Mojave 10.14.2
S3 - Major
OS: macOS 10.14, Arch.: x86_64, MuseScore version (64-bit): 184.108.40.20637, revision: c1a5e4c
Opening a .mscz file and then trying to save it causes Musescore to exit.
It will "save as" as .mscx file though.