By the way, I've tested the QLPreviewView and It's also affected by the same issue! So instead of using QLPreviewPanel, we could generate the thumbnail with QLThumbnailGenerator and then display the result in our app? It seems a lot of work for something Apple should fix 😅

Excatly the same issue with the same code used for years. Tested on macOS 26.0, 26.1 and 26.2 RC. My app is sandboxed, and access to the files is made through the NSOpenPanel first (Macintosh HD folder). Same log message and behavior: takes a long time. Can a DTS engineer tell us what's going wrong?

Thanks for your detailed answer, and your workaround. I hope you'll find a way to fix this issue ASAP 🙏

I can confirm that latest beta does not allow to bookmark the root folder "/" for later access. This leads to an error "The file couldn’t be opened.". Do you know if this will be fixed before the RC version of macOS?

NSPrefersDisplaySafeAreaCompatibilityMode should not be required for most regular apps. If you use standard API to go fullscreen, there's nothing to do on your side. The app will be displayed just below the notch. But I agree, there's a lot of confusion.