A few more other things I'd like to recommend that any editor would want to know:
It is good practice to delete ALL media cache after updating Premiere Pro to a new version or after updating the OS.
Avoids performance issues with trying to playback media using stale media cache.
Avoids export issues as fresh media cache is used rather than cache from a previous version.
When troubleshooting performance or exporting issues, delete ALL media cache, including your current media cache.
Again, you cannot delete all media cache from Prefernces unless all projects are closed, including the current one. Choose File > Close All Projects, then choose Preferences > Media Cache and choose to delete all media cache.
Adding these comments as I heard a couple of editors are having trouble as all their media cache didn't get deleted. Hope this helps those having performance and export issues!