media clip missing

I swap between my macbook and my pc. And I'm unsure how to start a project on my macbook and finish on my pc. When I save as and put it in the cloud. And then try and open it on my pc the cuts are there the text Is there the adustment layers are,  but the audio and media are not there and the media clip is missing window pops uop when I first  open it off the cloud.