ok having a bit of a zoom problem. not sure if its a setting or a bug or what. typically i know in almost every 3d program there is a limit to how far in you can zoom. eventually you zoom in too far and it slows down to a crawl then eventually stops. i rarely have this issue on the windows version and when i do you can just zoom extents or zoom to window, it will reset the zoom origin and you can start zooming from that point again. in this case on the mac version i can barely move. if i zoom extents o can move across the grid 4-5" and it just stops. its like the zoom origin is set super far away already and im starting near the end of my travel. i am using a space navigator but doesnt seem to matter. once it starts slowing i can try to continue with my mouse wheel and its the same thing. one thing i thought was odd is i dont even have to be zooming really. i had an elliptical object aprox 3" long, zoom extents which set me about 6" away. i wanted to zoom in and do a fly by to inspect the edge all the way around. i zoomed in to my start point, started the fly by, got about 3/4 of the way around and it completely stalls by the time i reach back to where i started. when i started it was perfectly fine but when i was done and ended back at the same point i started from in 3d space it was out of travel. this leads me to believe this is less about the actual zoom and more about distance the camera travels. in any case it makes it almost impossible to use. as mentioned i have windows and mac version. i dont see any of this in the windows side even using the same file. i dont fire up the mac version too often so i cant say how long this has been happening. i dont ever remember anything like this before.
It is a known issue, one work around is to select an item and zoom selected for working in close detail.