Final Cut X- Not Enough Media Error - for transitions I am on my trial here with version 10.2.3, its great but I get the above error when trying to put in transitions sometimes.

How to fix?
The error generally appears when the clips you are transitioning between do not have enough media to overlap. To avoid the message, trim the end of your clip(s) such that there is enough media to cover the transition.

The bug associated with this error message was fixed in Final Cut Pro X 10.3.