Need to restore a backup or import a project from another system into FCPX? It's not as simple as it seems at first glance. You would think that you could just double-click the project file but that produces the following error:
Final Cut Pro X is expecting projects to be contained in a folder inside your Final Cut Projects directory (or Final Cut Events if you are importing an event). The default locations of these folders are in ~/Movies.
To successfully import these files, you must create a new directory inside your Final Cut Projects or Final Cut Events folder and then copy the project to this new directory. FCPX will determine the project name from the name of the directory but the project file does not need to have the same name.
It's also worth noting that there is a difference between double-clicking an XML file and importing it via File > Import > XML.
Double-clicking seems to import the file without modifying it, so you will get errors if a project already exists with this ID or the event is not in the exact location as specified in the XML file. However, if you import it via File > Import > XML, it is more intelligent and will assign a new ID if necessary and find the new location of the event if it has changed.