Re-rendering required every time I re-open FCP...

This is an issue that has happened to some people over the years and it seems to still be unexplained.

The good news is that usually you don’t need to render. Most people just turn “background render” off and leave it off.

At this point it is probable that a lot of space may be used up by render files. Besides turning background render off in Preferences->Playback I recommend that you delete all render files - or at the very least the unused ones: select the library in the browser sidebar and go to File->Delete Generated Library Files.

Also, every time the application appears to misbehave, deleting its preferences is recommended. To delete preferences, hold down command and option while starting FCP X and click Delete Preferences. The application will start in a default state, and open an “Untitled” library.

Reopen the library you were working on, set the preferences the way you like them, and try again.

There are separate render files for proxy mode vs original media mode. If you switch view modes, you will may see lots of "render dots" because the render files in that mode are not up to date.

Simply relaunching FCP should not cause current render files to become "stale" or show as render dots.

However this is sometimes observed. One possibility is a 3rd-party plugin applied to an adjustment layer or a 3rd-party generator. If those are incorrectly written so that upon initialization, they invoke some minor change, maybe re-read their last saved state and re-apply that, it could cause the Motion runtime engine to mark that as "uncached". In turn every clip (up to the entire timeline) covered by that adjustment layer could become uncached.

Something similar could happen if using a 3rd-party plugin such as Color Finale. I have never observed that, but a standard troubleshooting method is first exclude 3rd-party plugins.

My first suggestion is do tests to see if the behavior happens everytime or just some time, if it's related to a 3rd-party effect or generator, etc.

E.g, duplicate your timeline, open that duplicate, select all clips with CMD+A and delete all effects with Edit>Remove Effects. Render that timeline manually via CMD+A to select all clips and CTRL+R to render. It's obviously best to do tests like this with background rendering disabled, and start with all render cache files deleted.

If the copy of the timeline with no effects does not show the behavior, make another duplicate but leave all the effects. Then delete the effects on 1/2 of the timeline, then the other 1/2, then 1/4, then 1/8, etc. to narrow down which effect is causing the problem.

All your media and libraries should be on a disk volume formatted as APFS or Mac OS Extended Journaled, not on ExFAT. If your media or library is on a NAS device, please describe the details. In any of those cases it's possible the "last modified" info might not be implemented correctly and could fool FCP into thinking the cache files were out of date.

Never mind. I’ve found plenty of LUTs that reproduce the problem.

Yes, deleting preferences resets everything to the default state. There is a free preference manager from digital rebellion that can save the current prefs and then restore them. In your case where you have a lot of customization AND the preferences might be suspect, I don't think it would be a good idea to save your current prefs with something like preference manager and then restore because you could be just reinstalling corrupt prefs. It's best to save them right after they've been created and are known good.

I am away from my mac but I am pretty sure that personalized keyboard shortcuts are NOT removed by deleting preferences. I have deleted preferences many times and still have several sets of “Commands” available.

Thanks. The behavior is very strange. I render and reboot the application. The render is lost. I re-render and reboot and the render isn’t lost. Some get lost and others don’t. Some get lost and only come back after more than one re-tender and reboot. After enough re-renders they all seem to stick. What a waste of time and space. Fortunately I normally never have to render.

If you are using proxies then you probably do not need to render. It’s irrelevant what the original media is. A 2015 mac should have no trouble with either ProRes or H264 material in 1080 (or lower).

They’re not removed, but the setting it changed back to the default layout.

Window layouts and other customization are in the zip file that appears on the desktop when preferences are reset.