FCP X 10.1.4 keeps quiting

FCpx 10.1.4 will only run on Yosemite.

Sure about that? Tech specs are still showing 10.9.2 or later.

Might trying trashing prefs first.

Now I am not sure anymore Tom.

Actually, it will run just fine in Mavericks. There are reasons to suspect this will be the last version to run in Mavericks, with MXF support. So that broadcasters who aren't going to update OS's for some time, can switch to FCPX easily and be supported. I know a few Macs with Mavericks running just fine with 10.1.4.

• I'd use "FCS Remover" from Digital Rebellion (dot com) to 100% remove FCPX from the system. Simply moving the app to the trash leaves a lot of system files that could be corrupted in tact.
• Run Disk Utility to "Repair" (Verify is a waste of time) all drives.
• Be sure all drives have at least 15% of their capacity as free space.
• If you have Disk Warrior, run it to repair the Directories on all drives.
• Then reinstall FCPX.
• Be sure the Pro App Support 2.0 update is installed, also.