I use both Windows 1.9 and Mac 3.0 version. And I use Dropbox to sync the projects. When I open the Scrivener on Mac, the projects will be updated automatically, then I cannot open them on Windows.
What should I do with this?
Thanks all!
Many thx! 
Welcome.
Apologies for the brevity of the first message. Was using a dodgy iPad on which the keyboard only works intermittently.