I have created a linked clip draped it in the time line and opened the clip in its own project by double clicking on the clip. Here I perfortmed audio and color edits. then I went back to the main project and the music plays but no video.
I think I understand it.
Dropped clip in Project
Used Open Clip so it opens in its own Project and you made audio and color changes
Back in the original Project there's no video.
I'll note than in FCPX 10.4 double clicking on the clip doesn't Open Clip in its own Project. I have to use the menu Clip>Open Clip (or assign a keyboard shortcut) to do that.
Are you in FCPX 10.4 or an earlier version?
When you say "no video" do you mean you don't see the color changes or do you see no video at all?
How did you make the color changes, plugin like Color Finale or Chromatics or built in FCPX Color Board or new Color Wheels?
I think generally you'd want to use Open Clip in the Event Browser and make changes there. Then you can add to main Project and every instance will carry those changes.
If you use Open Clip for a clip already in the main Project you should still be able to affect the clip though so it seems there's an issue.
In X, it helps to think think in Metadata FLOW. Metadata kinda flows from upstream to downstream along your workflow.
In EXTREMELY simplified terms: Import is stage A. Event browser work is stage B. Storyline operations are stage C. Export is stage D.
You're opening up a stage C asset - attempting to apply changes as if it was a stage B asset - thinking those changes will automatically re-flow into stage C. And in some specific cases the metadata flow will refresh. However, if you make a change to the stage B asset that confuses X - the result can easily be that your storyline can't parse those changes anymore.
I'd look at the changes you made directly after the "open clip" request. Did you add 3rd party filters? Did you apply complex processes like noise reduction or global color grades that may need heavy processing to finish calculating?
I could see those types of things establishing revised metadata flow that doesn't succeed in delivering the video frames downstream.
My initial thinking.
I hope you have good luck in tracking down where your data flow is getting blocked.