MS3 and MS4 cannot run at the same time

• Jun 28, 2023 - 18:27

I'm currently exporting several MS4 .mscz files to .xml so that I can edit them in MS3 due to a large number of substantial bugs in MS4 that make my work impossible to complete there.

I would like to be able to run both programs at once to help with this but if I try to open one version with the other already open, nothing new opens—it just refocuses on the app window for the version already open.


They should be able to run simultaneously. They work OK that way for me. However, only one program can be associated with the .mscz file type. When MU4 is installed it sets itself as the default program to open .mscz files. In windows you can right click on a score and use "Open with" to specify the program (i.e. version 3 or 4) that you want to use. You can also (via Windows Settings) change the default program.

If you are experiencing something other than what I described - i.e. if you click on a score to open it, it insists on opening with MU4 come back and explain in more detail.

In reply to by SteveBlower

I should have mentioned that I'm on Mac 13.4.1. But I meant what I wrote originally—this isn't about opening files. Whether opening a file or just opening the application period, the other program will not open if one is already running. e.g., the steps to reproduce would be:

  1. Open MS3.
  2. Try to open MS4.

MS4 does not open. The focus shifts to the already-open MS3 application.

Can you point to the GitHub issues for the bugs you are most concerned about? Almsot all of the critical ones submitted thus far are already fixed for 4.1, but you can also test for yourself using the beta build from the Announcements forum.

In reply to by Marc Sabatella

no, I don't know how they're categorized on GitHub but:

  • numpad keys not assigning properly
  • MS3 and MS4 can't be open simultaneously
  • can't have multiple scores open in a single window
  • removed "update existing score" toggle when publishing online
  • removed "sign out" button when publishing online

In reply to by mlavengood

It's by design that MuseScore no longer forces all scores into a single window sharing the same synthesizer and sound settings. barely tolerable in Mu3 when all we had was soundfont, but not viable in a world of VST's and Muse Sounds. Apparently macOS does not deal with these multiple windows as well as most other systems do, which is unfortunate, so workarounds are being investigated.

But numpad keys certainly work in general, and MU3 and MU4 can most certainly be run simultaneously. If you have a specific case where you are encountering some sort of as-yet-unreported problem, please be sure to open issues on GityHub with full details on how to reproduce the problem. Otherwise the developers won't know you are experiencing a problem and won't be able to start investigating. But, probably best to continue discussing the issue here first before going to GitHub. Since in general these things do work, it will take some work to discover what unique quality of your particular system is causing it not to - some third-party software causing a conflict, an OS setting you have enabled that most people don't, etc.

As for the updating of scores, the checkbox is returning in 4.1, due out next week. Meanwhile, as mentioned elsewhere, you can simply clear the source field in project properties if you don't want a score to update. Not sure what you mean about signing out, but MU4 provides that option on the Home screen. should you need to do that for whatever reason.

In reply to by mlavengood

Indeed, different keyboard and OS"s handle numeric keypads differently, so on some systems you may need to edit the shortcut file directly to assign custom shortcuts to numeric keys rather than their built-in functions, which should already work. This was true for many systems in MU3 also, FWIW - worked fine for some systems, not fur others. For Mu4, the method used to interpret key codes changed, so now some systems that used to have problems work better, and some that used to work better now have problems. It's been a never-ending battle as long as I've been with MuseScore (over 10 years). But that's one reason we provide the ability to export/import the shortcut definitions - to allow for editing in the cases where something isn't going well on your particular system.

In reply to by mlavengood

Indeed, thanks! I wanted to be sure that the issues you are encountering were actually being tracked. Now that you've submitted issues, work can begin on those. The numpad one, as I explained, has been a problem since day one, and so far no one has ever found a solution that works for everyone, unfortunately. But people can keep trying!

It will be interesting to see if anyone else can reproduce the problem with MU3 and MU4 not running simultaneously - certainly it works fine for me on Windows on Linux, and I hadn't heard any other reports of this. So while it might turn out to be macOS-only, I'd be surprised if it turns out to afflict all macOS systems or I'd have expected to have heard more reports of this.

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