musescore / musescore/MuseScore
Musescore studio refuses access to score when unregistered plugin Polyspectral MBC in mixer
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@zacjansheski is already working on this.
Since Dec 13, 2025.
crash
needs review
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Description
Issue type
Opening/saving issue
Description with steps to reproduce
- Load free trial of Polyspectral MBC from Musehub
- Install Polyspectral in a slot in the Musescore Studio Mixer
- Trial period expires.
- Attempt to open score.
- Score opens with overlaid dialog box as shown.
- Only interactor that is live is "OK" and clicking it causes the score to close.
Supporting files, videos and screenshots
In which versions of MuseScore Studio is this issue present?
4.6.4
Regression
I was unable to check
Operating system
MacOS 15.5
Additional context
The steps above are those I actually took. I do not know whether the effect happens in other scenarios where Musehub believes an installed effects plugin is not registered. While Musescore Studio replaces Musesounds with MSBasic when MuseHub (wrongly) tells it those Musesounds are not registered, it responds to an unregistered Polyspectral MBC by completely barring a user's access to their own music, which is excessive.
Checklist
- This report follows the guidelines for reporting bugs and issues
- I have verified that this issue has not been logged before, by searching the issue tracker for similar issues
- I have attached all requested files and information to this report
- I have attempted to identify the root problem as concisely as possible, and have used minimal reproducible examples where possible
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Assessment
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