I'm running Premiere Pro 2018 on an iMac at work (core i7 4GHz, 32GB RAM) and on a Macbook Pro at home (core i7 2.7 GHz, 16GB RAM). I have a project with mostly 4k footage. On the timeline, the bar at the top is yellow on all this footage when I cut it in. I can do a Render In/Out and it'll all turn green, which is fine. I have the scratch disks set to my external drive. When I take that same project file and that same drive and plug it into my laptop at home, when I open the project the entire timeline has gone "yellow" again. The render files are on the external disk, but Premiere refuses to link to them. When I re-render the same section of the timeline, Premiere creates NEW render files RIGHT NEXT TO the ones that are already there. Same size, same content, different filename. TBH it's kind of ridiculous that Premiere can't look and see that the render files are already there. So what I have now is double the render files which means double the disk space usage. Anyone else run into this problem?
What is the exact workflow you are following to open the project in the other machine? Are you getting any notification of missing media and options to re-link?
Is it possible to share a screenshot of the names of the render files created in both machines?
I'm not sure, but this might have to do with your Media Cache settings. You might need to store that on your external drive, then have your home machine reference the same cache. When you loaded up the footage on your home machine for the first time did Premiere create new cache and conform files? If so, my guess is that the preview files are referencing those cache files, which have a unique identifier, so nothing accidentally gets tied to the wrong clip.