If I capture a viewport to file, and in the save dialog right click as if to create a new folder… Rhino freezes up for a real long time with just the thinking whirlygig spinning around. It takes like five minutes to wait it out.
I have to make folders in windows explorer, then navigating to them in the save dialog is no problem. Just can’t right click in there or press the new folder button.
No problem with that here.
I suspect you have a drive letter mapped to an off-line resource, or to a non-indexed network drive so Windows has to go build the list before it can hand the results back to Rhino to display.
This is a pretty typical problem and not unique to file I/O in Rhino.
You could try deleting any mapped drive letters you have. Rhino isn’t the problem here. Rhino is asking Windows and Windows is spending the time to build the list.