How to recover mp4 and wav files after power outage?

Problem: Power was lost while I was making a recording. I found the MP4 and wav files but they are not recognized by any software. My guess is the end of the file information is missing. How can I recover these files? I tried mkvtoolnix and ffmpeg which only returned an error.

ActivePresenter version: 9.1.1

OS: Windows 10 x64

Notes:

Hi Fred,

You can upload the video and audio file to a cloud storage service like Google Drive, share the link and the access right to use via our support email at support@atomisystems.com.
We’ll give it a try, but we’re not sure if we can recover them.

Regards