@Steve Browne -

Check which navigation method you are set up with by going to the navigation settings option in the Settings menu on the board and setting it to Mouse which should result in the trackwheel zooming rather than scrolling.

Kiron

@Kiron Bondale 

Perfect. Thank you very much. I’d not had that problem before, but now I know how to correct it.

All the best,

Steve

Hello, my Miro froze and now after reloading, I find that my middle mouse button (pressing down the mousewheel) no longer works to move the board, instead I have to use the right mouse button for that. 
Scrolling by spinning the mousewheel still works.

Why did this preference change on it’s own and why does none of the two settings (“Mouse” or “Trackpad”) reinstate the former setting?

Thanks, Kiron — that solved it for me too! I had the same issue and didn’t realize the navigation mode had switched. For anyone else looking:
Settings > Navigation > set it to "Mouse" — the scroll wheel will go back to zooming as expected.

Saved me a ton of frustration!

For anyone just finding this thread like myself, you now have to right-click an empty spot on the board, then select “Mouse or trackpad” in order to change the setting.

On a side note, for some reason auto-detect just doesn’t work for me. If I use my trackpad, it gets stuck on trackpad controls and doesn’t change back, hence the need to find this setting to change it back manually. It would be nice if auto-detect worked properly.