Final Cut Pro auto save vault
One of the confusing issues with Final Cut Pro, is that when FCP peforms an auto-save function, it saves the current project into the auto-save vault.
In order to recover an earlier version of a project, you must go directly to the Final Cut Pro auto-save vault.
The Final Cut Pro autosave vault is located at:
MAC-HD/users/username/documents/Final Cut Pro Documents/Auto Save Vault/name of project
Make sure you copy the old project out of the vault to a new location, and give it a new name.