Zooming with mouse wheel

I used to be able to zoom in a view window with my mouse wheel but I can’t anymore. Must have inadvertently unchecked a box. Can someone tell me how to undo this?

There have been a few reports of the zoom factor being put at 1 in the Rhino options. Make sure that is either a bit bigger or smaller than 1 (depending on which direction you want it to zoom).

I sorry to be so basic but in what menu would I find that option?

Type _DocumentProperties in the command line or go to the File menu and select Properties… Then follow the photo below. HTH

Both you guys are awesome. That did the trick. Thanks, Rick