Syncing Scrivener Projects
Deskop/laptop[edit]
On Desktop work directly from a project stored within a Dropbox directory.
This project can be backed up locally using Scrivener's Backup preferences.
On another desktop/laptop Dropbox will sync the changes within the Dropbox directory. Open the file from within the Dropbox directory on the remote laptop/desktop. Again, local backups can be made on the remote laptop/desktop.
Never have the Scrivener project open on two computers at once.
iOS[edit]
Store the synced projects in /Dropbox/Apps/Scrivener/. The iOS Scrivener app will prompt to sync with Dropbox when opened. A list of projects will be displayed on the app home screen. Make sure to click the Sync button when opening and closing the project, or set preferences to sync when opening and closing the app.