Thanks!
All no to every query.
I'll do a full merge, to see if this helps, but so far the only thing that helps is to disable every scatter. EDIT: Full merge didn't help. I'll try rolling back Corona.
Even if every scatter viewport visibility is set to None it hangs when they are enabled. I turned off all mapping, distance, includes/excludes for every scatter, and it still hangs.
I enable the scatters, do an unhide (even is nothing is hidden!!) and it hangs... crazy
The worst thing is; If I open the problematic scene and just delete the scatters, the hanging issue remains. If I do lots of other cleaning; ie collapsing objects, removing distance maps, emptying the SME etc and then delete the scatters, it finally unhides quickly.
This is a scene I created in Max 2023 Corona 10. Yesterday I upgraded to 2024, Corona 11 (latest daily)... probably something there!