A soft edit may need to be rendered if it is the result of an aborted timewarp or dissolve. Soft edits that need to be rendered contain one or more frames displaying the message “Unrendered Frame”. You re-render, or force render, a clip using the Force Render command. You can force render clips that are locked.
Use the Force Render command to render:
Frames on the Desktop containing unrendered Batch FX display the message “UNRENDERED FRAME Batch.” See Managing Clips in Batch.