Some Clips Won't Render with Render Cache On

Hello all,

This problem relates to a few high bit rate clips in the timeline. Our editing machine cannot playback these files smoothly so we turned render source cache clip on. Before this editing session, this project has been through many historical editing sessions, and once we had the every clip "render source cache clip" on.

At the beginning of this session, we turned all render source cache clip off and selectively turned the setting on for a few high bit rate clips. Strangely, while most clips renders in the background, few clips will not render - their overhead red bar remains red.

I assume that using a once mismanaged historical editing project (that was once edited in earlier resolve version, like 11, 12, etc.) may cause unexpected problems in Resolve. So I am planning to migrate the project to a new one starting from scratch. Any idea of how I can perform this properly?

OS: Windows 10
Resolve: 14.3

Just one day after some simple tweaking... after switching those clips from render source clip to "render clip output", it just renders fine. I suppose the grade is too computing intensive.