Hello! I am close to giving up here now. I record videos in-game with audio from the game itself + that I speak into my microphone. The whole procedure works fine, I create an mp4-file. When I open that file in Win10 i see and hear everything, i.e. my speaking and the in-game audio as well as video. BUT, when I then upload that mp4-file into premiere elements to add my own intro video and outtro video I do not have my mic audio included when I click play in premiere elements - only video and i-game audio, but not my speaking.
So, mp4-file -> all ok in premiere elements -> no mic-sound available
Assuming this video came from a camcorder or phone, there are a couple of possibilities -- but we need to know a few things.
Which version of the program are you running on what operating system?
Open the video in the free download MediaInfo. In MediaInfo, set View to Text and then copy the text of the report it generates to this forum. With this detailed report we'll be better able to answer your question.