Cannot duplicate Projects inside an Event in FCPX

Hi guys,

Hope you can help me.

I have around 400 hundred projects inside an event. They are all very very similar. A model doing exercises on the floor: same shot, same scene. I edited the first one and I want to copy-paste the same color and position settings for the following 600 exercises that we have filmed. I did it with no problem until now, that I reached project number 424 and suddenly I cannot duplicate 424 to create 425. FCPX does nothing, no error message, nothing...I simply cannot duplicate this last project to create project 425. But if I go to project 423 then I can duplicate it to create project 425. 

See picture enclosed.

Why I cannot duplicate number 424 and I can duplicate number 423??. Seems stupid but it is a problem for me if I cannot duplicate the last project each time. It is time consuming for me if I have to go to the penultimate project to duplicate in order to make more projects. I need to arrive to 600 projects (equals to the 600 hundred videos we recorded).

Do you know why I cannot duplicate the last project and I can do so with the penultimate?

Thanks in advance!

For that many videos, I'd have created a custom effect to do that. And that's a really large number of Projects for one Event. Do you have one clip for each Project? That's not good media management. I'd have divided those exercises up into categories. I'm sure they're not all going into the same show, right?

I think we need to step back and figure out why you have a need for so many projects in one event.