Hello! I just discovered this program and I am really enjoying it. However, I keep coming across this issue when I go to rename some files. Can anyone let me know what I am doing wrong? Or what I need to do? I attached some screenshots of what my work and the error message I receive.
Can you try this internal version and see if you still get this error message?
Thanks for sending the example file I've asked for via PM.
I've analysed the file and it's not a FLAC file, instead it's FLAC wrapped inside an MP4 container. So the file is actually a MP4 file, which should be possible to edit if you change the file extension to .mp4 or .m4a.
FLAC inside of MP4 is, uhm, let's say, unconventional 
Oh, I see. I need find a audio file converter website or program! Thank you! I really appreciate it.
If you are familiar with the command line, you could use ffmpeg and something like
ffmpeg -i input.mp4 -map 0:a:0 -c copy output.flac
to extract the audio without re-encoding anything (where input.mp4 is the FLAC inside MP4 container you want to extract from).