Found the issue. mcdeployqt was using @loader_path's instead of @rpath's when the executable parameter was used and wasn't handling the libraries with loader_path's when signing. Fix here: https://codereview.qt-project.org/c/qt/qtbase/+/511503

I think I've found the issue, macdeployqt seems to be buggy. It has a parameter called -executable that you can use to add additional executables to be deployed, when -executable is added, nothing in the Frameworks path get signed. Without -executable it works. So the error is because none of the libraries or Qt Frameworks gets signed, just some plugins.

Support from Qt requires a commercial license, and this is primary a open source project with minimal donations from a few users. I've tried both the Qt forums and the mailing-list (interest), no answers. Looks like there are lot's of symlinks: jonas@ni214 build % ls -lh strawberry.app/Contents/Frameworks/QtGui.framework total 0 lrwxr-xr-x 1 jonas staff 22B Oct 10 01:56 QtGui -> Versions/Current/QtGui lrwxr-xr-x 1 jonas staff 26B Oct 10 01:56 Resources -> Versions/Current/Resources drwxr-xr-x 4 jonas staff 128B Oct 10 01:56 Versions jonas@ni214 build % ls -lh strawberry.app/Contents/Frameworks/QtGui.framework/Versions total 0 drwxr-xr-x 4 jonas staff 128B Oct 10 01:56 A lrwxr-xr-x 1 jonas staff 1B Oct 10 01:56 Current -> A