@watchmyfail First, goto the URL opera://about and take note of the "profile" and "cache" paths. Then, close down Opera and rename those 2 folders so that Opera starts with fresh ones.

If everything is fine then, you know it's an issue with your Opera profile and you don't need to reinstall. Then, you can just continue using the new profile and cache folder and re-customize everything etc. or you can close Opera, delete the new profile and cache folders and rename your old ones back so that we can try something else to delete in your profile folder to try and fix it.

Another option is to just goto the URL opera://settings/reset and reset just your settings to see if it helps. Always best to close down Opera and back up the profile and cache folders first though just in case.

UPD: ok so apparently launching from a standalone installation fixes the problem entierly, so thank you very much

You will lose all your opened tabs and clear your recently-closed tabs list, but goto the URL opera://about, take note of the "profile" path. Then, goto the URL opera://flags/#new-session-manager and make sure the flag is enabled```. Then, close Opera, and delete the "sessions" folder in the profile folder.

If you need your save you opened tabs, before you close Opera, close that "upgraded" tab (and any other tabs you don't want). Then, for each workspace you have in Opera, right-click on a tab, goto "save" and choose "all tabs to a speed dial folder". You can then rename that folder on the start page to the name of the workspace you're in. Then, after deleting the sessions folder and starting back up, for each workspace, right-click the corresponding folder on your start page and choose "open all in tabs". Once all done, you can delete those speed dial folders you created and empty the bookmarks trash at the URL opera://bookmarks.

If you don't use any Opera workspaces, you'll obviously only have to to the "save all tabs to a speed dial folder" once.

If you still have the issue, goto the URL opera://settings/onStartup and make sure the startup option is set to what you want. If you have it set to "open a specific set of pages", make sure that upgraded URL is not in the list.

If you still have the issue, check the properties of the shortcut you're using to start Opera to make sure it hasn't been modified to pass that upgraded page URL to launcher.exe.

If you still have the problem, goto the URL opera://extensions and disable your extensions one by one and restart Opera to see if one is the culprit.

If you're using Opera Sync, log out of Opera Sync before trying any of this. Then, log back into sync. If it happens again after logging into sync, you'll need to reset your passphrase at the https://www.sync.opera.com/ and close down Opera and delete your "Sync data" folder.