Are you sure about the AFC (.afc) format file? I have had a similar trouble a few month ago, and my MacBook Pro looks a lot like yours (mid 2015, 16GB, etc), but my audio file was a ’.aac’, as far as I remember (a concert of Angelo Branduardi, from a backup of iTunes files from Windows), and the issue was due to iTunes itself, in my opinion —— perhaps due to version of my AAC file (no more maintained?).
I have lost my file, by the way, and finally fired all my .aac files, as most of them crashed my Mac. (I have just verified, I only have .m4a & .mp3 now).
If not too late, could you try this:
- Import the file on your Mac with any utility (not iTunes itself), then
- Try to import the file into iTunes (or to open it with iTunes),
to see if you still have the trouble (so iTunes is guilty) or not?
Whatever the wrongdoer, could you look which audio types your iTunes library hosts, as follows:
Open Terminal (it's in the Applications > Utilities folder)
Go to the root of your iTunes music files by entering one of the following commands in Terminal:
cd "Music/iTunes/iTunes Media/Music"
cd ~/"Music/iTunes/iTunes Media/Music"
(Note: due to the space in ‘iTunes Media’ folder name, the quotes are mandatory.)
ask the system for your audio files with this command:
find . -type f -print | awk -F'.' '{printf("%s\n",$NF);}' | sort | uniq
or use
/usr/bin/find . -type f -print | /usr/bin/awk -F'.' '{printf("%s\n",$NF);}' | /usr/bin/sort | /usr/bin/uniq
If you get message(s) about something "not found" (all the commands must be typed on a single line, but cut & paste are allowed).