I got tired of booting into Sonoma to build. It's bad enough I have to boot into Monterey to get a 10.10,11,12 capable build. I've created a small app (~184k) which does nothing except manage the preview panel. The app has no menu or dock icon. I've built the app on Monterey but any OS other than Sequoia will do. I include the helper app in my main app's bundle. My main app communicates with the helper via a custom URL scheme. It took about 5 minutes to change the code in my main app. I no longer include the Quartz or Quicklook frameworks in my project. Simply removing the Quicklook framework will not work if Quartz is referenced. I can now build on Sequoia and the app runs on every OS I support. The only different behaviour is that if you do a ⌘Q while the preview panel has the focus, it will not terminate the main app. I could more than likely get around this but the main app terminates the helper when terminated and it's not worth the effort.

Including QuickLookUI as optional does not work. The app no longer crashes but QuickLook functionality does not work. The only true workaround seems to be building on Sonoma with Xcode 15.x. Does anyone know if this has been addressed in Xcode 16.1?