Reinstall Final Cut Pro
Follow these instructions in order to re-install Final Cut Pro on your system:
1) Switch to the Finder
2) Select the "Applications" command under the Finder’s "Go" menu.
3) Locate the Final Cut Pro application, and drag it to the Trash.
4) Empty the Trash
5) Click the link below to view the "Purchases" section on the App Store:
6) The list of your previous purchases should include Final Cut Pro. If you do not see Final Cut Pro in the list, please sign in using the Apple ID that was used to purchase Final Cut Pro.
7) Locate and click the "Install" button in the entry corresponding to Final Cut Pro to force the application to be downloaded and installed again.
8) When the installation is complete, restart Final Cut Pro.