Standalone viewer not default any more

Good sirs.
What do I need to reset/throw away to make DOpus the default standalone viewer?

Even though I have it set under Preferences/Double click On Files, Windows Photo Viewer has suddenly hijacked all my jpg viewing.

Thx

Another location is -> settings -> file types -> system file types -> search for the "JPG" entry. It should
be set to open with Opus viewer.

See the FAQ: HOW TO: Use the Opus image viewer inside or outside of Opus

back in business - thanks