@oP2 Sometimes that's just a bug that Opera has to sort out. Other times though, you can fix it yourself.
Close Opera and make sure there are no Opera processes open in the Windows Task Manager.
Then, hit Windows key + r to open the run dialog, type cmd and press enter to open a command prompt.
Then, type:
"%localappdata%\Programs\Opera developer\opera.exe" --show-component-extension-options
and press enter to start Opera.
Once Opera is started, goto the URL opera://extensions, turn on developer mode and click "Update" at the top of the page. Further, scroll through the list of extensions on the page and see if there are any separate update buttons for any extensions and click the buttons. Once done, restart Opera.