MuseScore is losing Jack connections on opening a file

• Sep 8, 2017 - 12:01
Reported version
S3 - Major

Actually I'm using MuseScore 2.0.2 on Ubuntu 16.04. However the bug report form doesn't allow selection of versions prior to 2.1.

My configuration:
On tab Input/Output of the settings dialog I configured MuseScore to use the Jack audio server. I activated the use of Jack audio, Jack Midi and re-establishing the Jack connections.
Jack connections are handled by the Catia patchbay application, which is using the A2J bridge.

Installed software from the KX-Studio repositories (
Cadence: cadence 2:0.8.1+git20170711
Jack server: jackd2 2:1.9.11+git20170722-1~xenial2
Catia patchbay: catia 2:0.8.1+git20170711

My observations:
- After MuseScore is started, it shows up as "mscore" in the patchbay with two audio outputs "left" and "right" along with Midi input "mscore-midiin-1" and Midi output "mscore-midiin-1".
- In Catia I connect my Midi keyboard UMX 25 to the Midi input of the mscore object.
- Everything is fine: I can play the sheet music as well as entering notes with my Midi keyboard and hearing them.
- When I open the another MuseScore file (strg-o), the mscore object disappears from the patchbay. Playing MuseScore files is not possible any more.
- After stopping and restarting MuseScore the newly loaded file can be played. The mscore object shows up in the patchbay again.

I like MuseScore very much and it has grown to be my main audio tool. In the audio setup of my PC using MuseScore in Jack mode is essential. Other Jack applications I use are Ardour and Hydrogen. Fixing this annoying bug would be appreciated very much.

kind regards
Alfred Peters

Attachment Size
Auswahl_049.png 54.74 KB
MuseScore: Einstellungen_050.png 63.15 KB


Selection of anything prior to 2.1 is for a good reason: you're supposed to run the latest version, in order not to reports bugs that had been fixed long ago.
Try an AppImage to see whether 2.1 has the problem too.

Hmm, not sure Jack works with AppImage? Anyway 2.1 should be available in the PPA?

Ok, my version from the Ubuntu repo is outdated. I tried the AppImage of MuseScore 2.1, but Jack doesn't work with it. No mscore object appears in my patchbay. And furthermore, there is no 2.1 in the PPA.
A switch from Ubuntu to Debian 9 with activated back-ports repo would solve my problem. But this is a major effort for me. Still thinking about it...