I also have the same problem & would like to update my opera password to make it more security-wise! Could someone in opera help us please? E-mail is penelope.sue(at)live.ca - Thank you in advance for your timely response.
Try at opera.com maybe. I'm here at the forums because I keep getting email in my google account that says my Opera password was reset. But it's always in different languages so I can't read it. But the sender is from firstname.lastname@example.org. Of course you can't use that, but maybe support at opera dot com? Or your names that you remember?
Look at About Opera (from the menu), it will tell you where your Profile folder is. In that folder, you'll see files named Bookmarks, favorites.db, etc. along with various .bak or .dbak and .journal files. You definitely want at least Bookmarks and Bookmarks.journal, but you might as well make copies of everything in your profile just to be safe.
I do see a "Reset synchronization" button in the Sync options dialog, but you have to be logged in to see it so that doesn't help. I wonder whether deleting the files in the Sync Data folder would work?