Specifically in the App Store, go to the Purchased tab, then click the Install button by FCP X after trashing. Sometimes just going back to the app in the regular Store will indicate you have to re-purchase it.
Also be sure you're logged in with the same App Store/iTunes account that FCP X was originally purchased with.
I am about to do this but nervous because after I trash the app, in the Purchases Tab, does it recognize that it's no longer there and change it's status from "INSTALLED" to "INSTALL"?
Or does it say "REINSTALL"?
If the Purchases Tab doesn't say this then I'd have to repurchase presumably and that would suck!
The account is the same one that originally purchased it last year.
Instead of trashing the app can't I just hide the app on a hard drive to experiment?
Yes, if you are worried you can hide the app somewhere else ......... anywhere out of the Applications folder will do.
However, you may be able to solve your problem - whatever that may be, by trashing the preferences.
Many weird things happen as a result of corrupt preferences which can create a vast range of different symptoms, so whenever FCP X stops working properly in any way, trashing the preferences should be the first thing you do using this free app.
Shut down FCP X, open PreferenceManager and in the window that appears:-
1. Ensure that only FCP X is selected.
2. Click Trash
The job is done instantly and you can re-open FCP X.