I have Audition (I think it's CS6) on a desktop Mac. I always use an external HD to save all of my sessions. Today I downloaded Audition CC2019 from the Adobe Cloud onto my Macbook Air, and plugged in my HD to start editing. (I'm editing a session that I started on the desktop Mac at home). It opens the session with no problems. It works and I can make cuts and edit fine. BUT!.. When I try to save the session I get a message that says "one or more media files used by this Multitrack session are located outside of the session folder. Would you like to copy these media files to the session folder?" It makes no difference whether I say yes or no because when I quit Audition, I get this message: "Save changes to [session name] before closing?" so I say yes and then I get the first message again! If I say yes, I get "Audition encountered an error trying to perform the operation" and if I say no, it will close down without saving anything and, when I open it again, I have no saved edits. I'm going to cry!!
Is there a way around this? I'm away from home for two days and need to edit! Has anyone had this problem before? Is it the fact that they're two different versions of Audition? Or is it something blindingly obvious? I'm going round and round in circles and wasting so much time!!!
One thought occurs to me, which may have a bearing on your problem: CS6, if that is indeed the version on your desktop Mac, is 32 bit only; CC is 64 bit only.
First of all can you open a session from your external hard drive and then save it onto the local drive using Save As?