Users trying to use crontab -e and VI (haven't tried other editor) will
find that when they try to save the cron job they will get a message that
says "crontab unchanged" and crontab -l shows that no crontab has been
entered. This goes for all users, and it doesn't matter if you set up
a /etc/cron.allow or not.
*** This bug has been marked as a duplicate of 25992 ***