As soon as I updated to 2.7.3 (because the promotional banner in 2.7.2 would not go away no matter how many times I dismissed it), I received the following error:
Postman: wp_mail has been declared by another plugin or theme, so you won’t be able to use Postman until the conflict is resolved.
More info that may help – /home/thessewt/live/thesinglegourmet.net/wp-includes/pluggable.php:174
wp-includes is part of the core of WordPress, not a plugin or theme, so why is this happening?