opening a quite complex Rh6 file, saved small on the Windows side,
opening on Mac - the Version Warning Dialog stays white / blank.
Your file xxx.3dm is a Rhino V6 file.
maybe calculating the meshes somehow interferes with the dialog.
workaround is quite simple:
just press enter while Rhino has focus.
Version 7 (7.11.21264.11002, 2021-09-21)
mac os x 10.15.7