Choose Default App opens when I open Opera
Odd thing has started the last few days. Using Win 10, 64-bit, and when I start Opera, either by the app itself or by a shortcut webpage link on my desktop, Opera comes up WITH "Choose Default App" window from Win 10 where I can choose file associations. Any ideas on that one? I have changed it so that Opera starts with a blank window, with a web page, with various other starts and don't know why Windows is doing that.
Running Opera in Windows 8.1 compatibility mode has fixed this issue for some. You could also try reinstalling Opera but make sure to backup your bookmarks and other important data.