Opera Help

Use other programs for certain actions

Settings > Preferences > Advanced > Programs

Choose which programs Opera should use to handle specific protocols.

Protocol manager

You can create your own list of programs to launch when executing particular protocols in Opera. The default list includes:

Protocol Purpose
mms Choose which application Opera should use to display MMS streams
rtsp Choose which application Opera should use to display RTSP streams
mailto Choose which application Opera should use for email; Opera's own built-in client, the default email client on your computer, or a specific other email client.

You can ask Opera to make sure at each start-up that it is the default browser on your computer.