RE: [Opera 25] Why bookmark import is not working?
In the mean time, if you saved your bookmarks as a *.adr file (Try searching your computer for *.adr), just copy or rename it to "opera.html". Then open that file, and bookmark it. You will be able to see all your old bookmarks!
I don't work for opera - I'm just someone who played until I got something to sort of work, because I was desperate. The *.adr files aren't really *.html files, but they can be read by most browsers.
It would be very hard to simply import it to the current Opera 25 - because the old bookmarks were hierarchal, meaning that you could have nested sub-folders, whereas the Opera 25 bookmark page doesn't seem to be.
But I look forward to Opera 26, for this.