On my Mac, "Relaunch to update" does nothing. What is wrong?

On a Mac, BookyAI can only update itself when it is in your Applications folder. BookyAI arrives as a zip file; when the app is opened from Downloads or straight from the unzipped file, macOS runs it from a protected copy that the updater is not allowed to replace, so the new version downloads but the install silently fails. The fix takes a minute: quit BookyAI, drag BookyAI from Downloads into your Applications folder, open it from there, and press "Relaunch to update" again. From version 1.9.19 BookyAI notices this itself: when it runs outside Applications it offers to move itself there at start, in one click, and the update panel says "Move BookyAI to Applications first" instead of pretending to install. Your books and settings are kept wherever the app is; moving the app does not touch them.