If you have designated QuickTime Player as Final Cut Pro's external editor for video files, you might find that the Send To Motion feature fails to open the resulting Motion project in Motion. Instead, the .motn project opens in QuickTime Player.
In the majority of workflows, it is not necessary to explicitly designate QuickTime Player as the external editor for video files. If you clear the setting so that no application is selected as the external editor for video files, Final Cut Pro will use the application that Mac OS X uses to open video files, which by default, happens to be QuickTime Player.
Follow these steps to clear the setting for external editors
This document will be updated when more information becomes available.