My Bari Sax clef in the score is shown as a bass clef. The Bari Sax is a treble clef instrument and is correctly shown as such in the instrument panel, and the Bari Sax part tab shows it in treble clef. It is only shown as bass clef on the score tab.
Comments
This is because you are in concert pitch mode. In concert pitch, the bar sax notes would be far too low to display in treble clef without tons of ledger lines, so MuseScore defaults to bass clef instead. If you prefer, you can switch to the treble clef with the little "8" below it (also used for tenor sax in concert pitch mode) by making the change while viewing the score in concert pitch mode. MuseScore remembers which clefs you are using with concert pitch on versus off.
In the future, it is better to use the support forum (Help / Ask for Help, from within MuseScore) to get information on how to use MuseScore.