I can't import a .mp4 into version 14.3

[stonewallsdaddy]

I created a short animation in After Effects CC. I used the latest version of Media Encoder to create a 1920x1080 30 fps MP4. When I tried to use Premiere Pro 14.3 to edit and add a music track, the video would not import. In fact all of my previous .MP4 videos show if the media browser as an icon, not a thumbnail and would not import either. I could however import a .MOV file. 

When I switch to Premiere Pro 12.1.2, the MP4 showed up as usual and loaded as expected.

I have both systems set to software render. 

[Addam Media]

I am having the same issue, cant open any of my sony a7rii and a7iii footage, i have to revert back to version 14.2

[stonewallsdaddy]

Update: The latest version of Premiere Pro that will open the file correctly is 14.1. I tried the latest version 14.5 today and it still will not load any of my MP4 files all of which were all created with Premiere Pro ver 12, 13 or up to 14.1