problem of fcpx 10.4 under hight sierra 10.13.3

Hello
I have a problem of fcpx 10.4 under hight sierra 10.13.3 my timelines is red i don't know how to solve

You most likely have media in the project that is offline; in other words maybe on an external drive that is not connected or powered up. Also, if you moved any of the clips used in your project to another location, they will appear as offline (RED) and need to be relinked. This can also happen if the clips used an effect that is no longer on your system. If you post a screenshot of your timeline it may be helpful.

Hello there,

I don't think that's the problem. Same thing happened to me and what turns red is the whole area of the timeline (at least in my case), not just the content blocks. After much investigation I had to call to Apple and a FCP expert had to take control of my computer remotely and changed several things until he resolved the issue. He told it was something very unusual, so I guess you'll have to talk to them.

Good luck!