To fix, add this to your vimrc: au BufWritePost * :if &fenc=='utf-8' || (&fenc=='' && &enc=='utf-8') | exec "silent !xattr -w com.apple.TextEncoding 'UTF-8;134217984' \"%\"" | endif This will append the extended attribute in every file you save with a UTF-8. Note that % is in double quotes to escape spaces for the shell. The :silent command prevents Vim from displaying the results (which are empty). If you want this for .txt files only, use the following instead: Using the command ls -l will show '@' in the file's attributes, for example: -rw-r--r--@ 1 daniel staff 15 Jun 5 10:12 lol.txt