Hide your Libraries in a (temporary) new folder, then launch FCP X. If it creates a new Library, and launches OK, you probably have corrupted media or render files in one or more existing Libraries.
Quit the application, and drag one Library back to its original position and launch FCP X again. If that opens, repeat the process until you find the faulty Library.
If FCP X doesn't launch when there are no existing Libraries, Uninstall it following Apple's instructions and reinstall it from the App Store (using the same login that the app was bought with).
rsuri1012 wrote:
Also, seperate note - how do I add a movie project from one library to another library?
You can COPY a Project to an Event in another Library by clicking on the Project and dragging it, or you can MOVE the Project to an Event in another Library by dragging (as above) but pressing the Cmd button a moment before you release the mouse to drop the Project into the new Event.
When you release the mouse, a window will appear telling you what's going to happen - if it's not what you want, you did it wrong.
Andy