BLACK FRAMES AFTER RENDER

I've been editing on FCPX since its inception, and never had this problem before.
Any clip that sits on my timeline. Magnetic or secondary, does not render properly. I get issues of dropped frames, like intermittent black flickers. I've attached sample images of what happens during render. It does not happen continuously, it renders randomly and the end result is the black frames.

This happened on -- .mov proxy footage shot on Alexa. -- .r3d transcoded to Prores HQ --.mp4 canon 5dmk3 files. I could say almost everything I import causes issues.

FIXES THAT DID NOT WORK
1. Trashing preferences.
2. Re-installing FCPX 10.2.3
3. Deleting everything and rolling back to FCPX 10.2.2
4. Changing Location and Drive Permissions on the Library .fcpbundle in question.
5. Deleting Generated Files.

Nothing.
But I guess the only thing that I haven't tried is getting the .fcpbundle into another system and checking if the issue persists there too. But I cannot do that right now, as I'm in the middle of a project.

I have moved temporarily to Premiere, by using xto7 generated .xml. But I'm trying in vain to get FCPX back to where it was.

Any help would be greatly appreciated.

MY SYSTEM SPECS:
MacBook Pro (Retina, 15-inch, Mid 2014)
2.8 GHz Intel Core i7
16 GB 1600 MHz DDR3
NVIDIA GeForce GT 750M 2048 MB

SOLVED.

STEPS

Created new user with Admin Privileges.
Moved .fcpbundle into an External HDD.
Guess it was a permission issue after all.