MuseScore 2.0.3, JackAudio 1.9.10, LoopBe1.6, MiniHost 1.64 startup sequence on Windows 7 sp 1

• May 29, 2016 - 17:52

First, this is not a support request or bug report for MuseScore. I'm enthralled by MuseScore and can't thank the developers enough for their efforts.

The above setup does work... eventually. I have not been able to start the system up from a clean system reboot and have it work the first time. As a professional software developer, this is a little embarrassing. Some combination of rebooting JackAudio, MiniHost, and Musescore does the trick, but I can't figure out what that combination is to save my life.

I've gotten to the point where I can get both the midi and audio connections established right away, but then I get periodic midi dropouts (entire chords are missed) during playback. I would think it was a compatibility problem except eventually the system works perfectly (after numerous restarts of the individual components).

I can't figure out what I do to make it work.

So, is there anybody out there who uses this setup and gets it to work the first time? If so, what order do you start up the various components? Do you disable any services or anything like that?

Any help would be very much appreciated.


Thanks for the link. That page didn't contain the solution, but it's definitely something people should know about.

I ended up replacing JackCtl with KxStudio's Catia and set the server priority to 95 (-P 95 on the command line). One or both of those did the trick.

Hi there,

I've been using JACK output with MuseScore on my Windows system for a couple of years now, first on Windows 8.1 and now on Windows 10 and have worked out several things which are not immediately obvious.

JACK and LoopBE do not like each other. Having LoopBE active while JACK is running will result in XRUNs (dropouts) appearing quite regularly in the JACK message window. LoopMIDI is better, but you can still get the odd XRUN. This is undoubtedly the cause of the MIDI dropouts you are experiencing. It is far better to eliminate the use of a software MIDI THRU altogether......

This has led me to use KXStudio's Carla as a VST host, which, as it directly connects with JACK eliminates the need for a third party software MIDI Thru. The only slight problem is that Filipe hasn't yet implemented VST 32/64 bit bridging in Windows (or hadn't last time I checked for a new build) so you need to have both 32 and 64 bit versions.

So my setup is now MuseScore 2.0.3 JACK 1.9.10 and Carla 2.0 beta 4

Incidentally there is a new Windows build of JACK imminent - 1.9.11 is under test now.

Hope this helps

In reply to by ChurchOrganist

"Hope this helps"
You have no idea how much. Really.

Carla is giving me fits. How did you get it to work with 32 bit VSTs? I am using Carla 1.9.6 (2.0-beta 4). I'm executing the Carla-2.0beta4-win32 version. I've copied the 32 bit version of Kontak 5 Player to its own folder, set the path correctly, and the Carla discovery exe does load it without error, but when I try to load the plugin, I get an error message saying that the build of Carla that I'm using can't load that plugin.

Once again, I'm clueless about what I'm doing wrong. I am learning how to accept that.. slowly.

By the way, if you're in forum contact with the developer, would you let him know that if the discovery exe hangs up, you can't kill the cmd process in which it's running? I tried everything I know to do and ended up having to reboot the machine. That's pretty unfriendly for a Windows app. Would you pass on a request that he look into that when he has the opportunity?

Thanks for your assistance,


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