MainStage wonky laid concert because the application freezes at the plugin scan, even after removing the problem plugins.
MacBook Air, macOS 13.2
What I would try is making a copy of the Concert first. Then control click on the copy and select "show package contents"; you should see Concert.patch, control click on that and select "show package contents"; delete the patch(es) with the problem plugins. Then try to open the copy of the concert. Good luck!
OK, so it won't load ANY concert; I had read your issue as your specific concert.
In that case try opening a command window and entering "auval -a" without the quotes; this will scan the plugins and show up any issues which might help to pinpoint a problem.
It’s not a concert issue.
Mainstage freezes at the Audio PlugIn scan...I have removed the plugins that were causing the problem, but it won't load the concert because the software freezes at the scan.
