“How do I adjust the render setting so that the small changes I make don’t result in a “red” un-rendered bar?”
RT settings need to be set to “unlimited” rather than “Safe”
i cant rembere if that’s in FCP USer Prefs (option Q) or FCP System Settings (Shift Q)
reason i cant remember is i always set it the simple way: the RT menu top left of timeline.
“all of my video was displayed anamorphic in the viewer and compressed to Apple Pro Res 422. After the re-install, most of it is 4:3 letterbox”
what, in the Viewer?
that’s near on impossible
or do you mean once you have edited into a timeline?
in which case you sequence settings do not match your footage.
go to FCP A/V settings (option apple Q) and chose an appropriate sequence settings.
you have to put a tick next to it, not just have elected in blue
nick