• Goto the URL opera://bookmarks and export your bookmarks just in case.

If you want to backup your opened tabs, right-click on a tab and choose "save all tabs to a speed dial folder" first. Then, if anything happens, you can import your bookmarks back in. Then, you can right-click on that speed dial folder and choose to "open all".

• If you sync your passwords, goto the URL opera://settings/passwords, click on the kebab menu (3 vertical dots) to the right of "Saved Passwords" and export your passwords to a CSV file.

Then, if you ever need to import your passwords, goto the URL opera://about, take note of the "install" path and close Opera. Then, open a command prompt and run:

"C:\Program Files\Opera\launcher.exe" --enable-features=PasswordImport

(adjust the path to launcher.exe to what opera://about says).

Then, you can goto opera://settings/passwords in Opera and use the same menu to import your passwords back in. Then, you can close Opera and close the command prompt and open Opera from its icon.

• Goto https://sync.opera.com/ and reset sync.

• In Opera, sign out of sync if it says you're signed in.

• In Opera, goto the URL opera://about and take note of the "profile" path. Close down Opera and use Windows Explorer to goto the profile folder. In the profile folder, delete the "Sync Data" folder.

• Start Opera and set up sync like you never set it up before.