I recently did the first draft of edits on a project, and while the clients review the edits, I decided to get the color grading done. I figured that I'd do the color grading in another timeline set up for color grading. Once I got it right, I could either a) copy the color correction effects settings to the appropriate clips in the edit, or b) export copies of the original video files to new files, and then replace the originals in the edited timeline with the new, color-graded files. I decided to try b), mainly as an experiment.
Anyway, when I tried to replace the original files with the color-graded files, I ran into problems. Simply replacing the files meant that every clip now began with the new clip's start. Trying to replace with the frames and cuts matching (source monitor, match frame) gave me an error about "insufficient head data." I've been unable to find any online information about what this means. (The new versions are the same lengths as the originals.)
Forget a and b and just grade the edit.