Updated to the windows 10 20H2 and media encoder no longer exports my projects. I have been forced to use the innate exporter in Premiere and AE.
Installing version 14.4 of Media Encoder solved this issue for me.
Just putting this here incase someone is looking for more than one solution:
I found that my Media Encoder started crashing when I was using the GPU enhanced render, but was fine when using software only, so I rolled back my GPU drivers and resolved the issue.
This helped after a long deep dive to why media encoder kept crashing, even before I hit the render button when setting up a video in the queue.