Apple has published a troubleshooting basics guide with plenty of links for pro editors to access, in case they’re having trouble with the revolutionary NLE. You can access it here on Apple’s support page. There is plenty of good information, including how to back up FCP X Events and Projects, supported media formats and cameras, and much more. These are the basics, but you can always get more help and troubleshooting tips from the Apple Support page and forums, websites and forums like Digital Media Net (plus their forums), DV Info Net, FCP.co and others.
Hat tip: FCP.co