thanks for your replies.

Afaik Opera will "send" the link to the default program that is set to handle the protocol.

I don't have anything installed on this PC that handles magnets. Nor can I. It's a work PC.

Seems to be caused by security changes in Opera 21.
Hm, maybe right-clicking the magnet link and selecting "Copy link address" won't satisfy you?

I suspect you may be right.

The copying links does work, it's just cumbersome - before it was much quicker to do and could mostly be done with the keyboard - once the links where opened in new tabs. Now it's much much slower requiring mostly mouse work.