Saving Rhino 6 to Rhino 5?

So I am trying to save a Rhino 6 file to a Rhino 5 file so I can switch computers, however my laptop (a MacBook Pro) is saying “the model contains information that cannot be saved in a Rhino 5 file.” and then gives me options to save as a Rhino 6 or a Rhino 5 file, but when I choose the Rhino 5 file option, it still saves as a Rhino 6… Help!

Please post a screenshot.
My guess is you are confused by the interface.

Yes, there are thinks tht can be in a V6 file tht can not be in a V5 file. That explains the warning,
But you can still save the file as a V5 version file.