Adobe Premiere Pro CC 2020

[ThatOnePixelNerd]

Whenever I try to import a .mp4 it just crashes and refuses to respond.

[John T Smith]

MP4 is a wrapper, what is inside YOUR wrapper - Exactly what is INSIDE the video you are editing?
Report back with the codec details of your file, use the program below
Free program to get file information for PC/Mac http://mediaarea.net/en/MediaInfo/Download
- when you analyze your file in MediaInfo and post a screen shot in the forum, do so in TREE view

Does your video use a Variable Frame Rate? See https://community.adobe.com/t5/Premiere-Pro/Variable-frame-rate-video-with-Premiere-Pro/td-p/4601935
If yes, use https://handbrake.fr/ open source transcoder/converter to convert to Constant Frame Rate