Looks like my own stupid fault, but I'm installing the bundled melodyne essentials on a new PC and I can't authorise it because I've forgotten my username on myCelemony. I've emailed Celemony support, but just wanted to warn others to make a note of your username. Incredibly, you can reset your password via your email account, but there's no reference to your username in emails from them, and I don't appear to have any other emails with the username in. If anyone's had the same problem, please let me know if I'm missing something.
Thanks
Simon