weird behaviour

Hello!

I'm experiencing a very weird behaviour of my fcpx 10.3.2. I was about to finish an editing project and suddenly the timeline is not playing random video clips. Sound is OK, but no picture. Some of the clips are played fine, some - just black screen. Those clips which seems to be damaged have the unrendered stripe which never renders. The background task icon is behaving like crazy - constantly showing render process, but very fast, like it was rendering thousands of small clips. I left it for night hoping that it will stop but this morning the whole thing continues. Tried copying whole project into another project but the same thing, the only exception is that almost all clips now are black.

When checking the original files (reveal in browser -> reveal in finder) everything is fine there - both original and high quality media files are OK, they play fine and there are no damages. Tried copying for new from camera card, imports fine but when placed into timeline goes black again or has the strobe effect (few frames video, few frames black).

Anyone has suggestions how to solve this?

I have MacPro with MacOS Sierra version 10.12.2.

1- Turn background rendering OFF.
2- Delete ALL render files.
I'd then relaunch FCPX to delete preference files just to be safe.