FCP 7 and El Captian are not friends

I've recently had to update computer with Mac OS to El Captain. And I do not recommend to do it if you're going to use old FCP 7 on it. The main problems I have encountered until now:

1. Log and transfer - the most painful  - it works for short clips, but it crushes very often, and if I have spanned clips (like long interviews) it crashes and I can't do anything. 

2. Keying - green/blue screen keying doesn't work - the color of greenscreen is identyfied each time differently - it could be violet, brown, anything except green or blue. 

On the other computer I've got Mavericks  - and it works without problems mentioned above. So if you need to upgrade your old system, better go to Mavericks, not to El Captain.