genaldar's advice is what you should try first, if that fails, delete the partnership and try again - if that fails, let us know.
i have tried this on several occasions previously. it was my first step.
i have just done it again for good measure, to no avail.
i have now given up (really desperate for a sync...) and, after backing up my device with sprite backup, i have reset it to factory settings.
i was going to restore my calender and msgs, then reinstall each program one by one...
but of course now it will not run the backups, since sprite is no longer installed ("the backup .exe files are not digitally signed")
oh yeah - and it still is not recognised by my pc so i am unable to reinstall dprite (only have a installer, no .cab)
so now i have a virginal (read nasty standard orange settings) m600 and no way to bring it back up to speed without typing in my hundreds of contacts and appointments by hand - and this kind of defeats the whole point of the technology does it not?!