I'm running Premier Pro CC2017 and I notice that if I copy and paste a completed project file, where everything is edited and rendered the way I want, that when I open the copy, the complete timeline has the red bar over it and I have to re-render the whole thing before I can work with it. Why doesn't the copy stay rendered?
Are you copying and pasting the Premiere Pro project file only? To a different drive? Different folder?
That file in a different location is expecting background renders to be in the same location relative to the original project file location. When you put that file in another location, you break those links.
Dell Precision T7600 (x2)
Win 7 64-bit
Adobe CC 2015.02 (as of 6/2016)
256GB SSD system drive
4 internal media drives RAID 5
Typically cutting short form from HD MP4 and P2 MXF.