[Aaron Brown]

Great news! I had the same issue with .avi files not being able to be imported and the tool below worked well to quickly convert my files into .mp4.
This is a set of free tools, though I recommend a donation as they deserve it, that convert files to different formats.
In this case using either the MediaER converted it to a .mp4 file and the proresER converted to prores. Both worked, but the .mp4 file size is much smaller.
https://audiospot.audio/audiospot-creativetools