Audio Out of Sync in Premiere Pro CC 2020

[A.A.K]

Hi! 

So this is the second time this has happened. I create my sequence, do all of my editings, and save my premiere pro project. I open the same project the next day and all the audio in my sequence is out of sync!!!

The first time, I couldn't find a solution so I had to manually go through each clip to find the right point.

Please help so I won't have to do this again!!

I'm using Premiere Pro 2020. I have a Windows computer. All my files are mp4. The video I created is under 3mins long and I'm not using lots of effects. 

I also noticed that the audio is out of sync in some of the imported files as well!?? I have no idea how that happened but I'm guessing that is why they are out of sync in the timeline. 

I have tried re-opening the project which somehow fixed the audio issue on some of the clips but not all of them. 

Any help is appreciated. Thanks!

[Jeff Bellune]

Are your mp4 files variable frame rate? You can use a tool like MediaInfo to examine the file.

If it indicates the footage is VFR, you can convert it with Handbrake to constant frame rate. The converted files should have in-sync audio after import.