Hmm. On my Opera 12.14 installation, the manager opens and closes almost instantly. Perhaps it has to do with the number of cookies one has on their browser? I keep my cookies restricted to first-party only, with 'delete new cookies upon exit' set, so there will only be 10 or 15 cookies typically present when I start up the browser (mostly log-in cookies that I retain by first saving them with cookie deletion turned off, then restarting Opera to make those cookies into 'old' cookies, then re-establishing the cookie-delete-upon-exit setting.