Two attempts to eliminate the pesky sendmail popup weren't effective.
(1) A new username & login eliminates the pesky popup, but it also eliminates
access to all my files.
(2) I used "sudo mv libfm libfm-save" to hide the libfm folder. No effect.
Other candidates for exclusion from ~/.config:
caja, gtk-3.0, menus, tilda, caja-actions, ibus, mimeapps.list,
Trolltech.conf,
classicmenu-indicator, leafpad, pcmanfm, update-notifier, dconf, libfm-save,
plank,
user-dirs.dirs, folder-color, libreoffice, pulse, user-dirs.locale, gtk-2.0,
mate-session synapse, xfe
Might one of these other configuration files be the culprit ?
Thanks,
George Langford