If you right click on an empty spot in the treble staff you can access the piano roll editor (PRE), hit the play button and verify the grace notes are being played. With playback off, you can click on a grace note and watch it "light up" yellow in the PRE:
Comments
You wrote:
Grace notes don't play at all
If you right click on an empty spot in the treble staff you can access the piano roll editor (PRE), hit the play button and verify the grace notes are being played. With playback off, you can click on a grace note and watch it "light up" yellow in the PRE:
See:
https://musescore.org/en/handbook/3/piano-roll-editor#Opening
If necessary, you can adjust the playing times of notes here.
Also, I see you have added a staccato dot to your grace note. (It creates a noticeable gap in the PRE before the next note, the F#, is played.)
Perhaps you meant to use the acciaccatura -- a short grace note
See:
https://musescore.org/en/handbook/3/glossary#acciaccatura
and:
https://musescore.org/en/handbook/3/glossary#appoggiatura
and:
https://musescore.org/en/handbook/3/grace-notes