Playback not starting in timeline

I have been experiencing this ever since, but now it's becoming a bit excessive:

I open an edit (project) in the timeline. I go to the timeline and press PLAY. It works. But now, when I cut out a section for example, and I press PLAY it won't play. I move the playhead and press PLAY. Nothing. The playhead just won't begin to play.

There are many variations on this but they have one thing in common. The only way to get the timeline to play again is to "re-open" it by double clicking on the project in the overview section.

Any ideas at all?

I am on a MacPro2013 with all the latest OS and updates....

Thanks for chiming in!

What all is in this Timeline? Does it to this to all Timelines, or just one, or just a specific couple?
Have you tested with a single 10 second clip in a Timeline?
What codec is the footage you're using?
Any plugins being used, what specifically?

Hardware specs?

Known bug. Well I don't know if Apple knows it, but I do and I've reported it to them. Double click on the Project file you are working on in the browser to "reload it". EDIT: I didn't even read the entirety of your post but it seems you found the solution. Usually this happens when I'm adding transitions to audio files that are not wedded with video.

Redifer wrote: Known bug. Well I don't know if Apple knows it, but I do and I've reported it to them. Double click on the Project file you are working on in the browser to "reload it". EDIT: I didn't even read the entirety of your post but it seems you found the solution. Usually this happens when I'm adding transitions to audio files that are not wedded with video.

Yes that is it. But at the moment I am having to reload the project after EVERY edit I make.

But I found first solution for the moment: The problem does not occur for me when I use the "Standard" workspace where everything is on the same screen. I am experiencing this only with custom workspaces,

The timeline has 720p24 Porrees Proxy Clips. I am doing simple trims at the moment.

CONFIRMED - Problem does not exist in default workspace. Digging deeper into it, it seems the problem ONLY exists when the browser is in LIST mode. So it's an issue with the LIST mode. Problem is, I can't even imagine trying to sort through everything in the other mode, just too messy. The only time I don't use list mode is when editing Voiceovers because I need to see the waveforms as I edit so I can decide what makes it to the timeline.

This was happening to me in June 2020 and I found out FCPX didn't like my audio interface. As soon as I changed my system preferences Audio Output to default (built in) speakers everything played normally.

Frustrating as I'd prefer my studio monitors but at least I can still chop away. Hope this helps someone!

This worked, switching audio output made the timeline play again. Simple solution.