Работаю на Альт Образование 9.1. При попытке запуска onboard:
user@host-184 ~ $ onboard

(onboard:5711): dbind-WARNING **: 18:16:57.131: Couldn't connect to accessibility bus: Failed to connect to socket /tmp/dbus-45Zncq8Deu: В соединении отказано
18:16:57.235 WARNING Config: mousetweaks GSettings schema not found, mousetweaks integration disabled.

(onboard:5711): Gtk-WARNING **: 18:16:57.249: Theme parsing error: colors.css:71:44: Invalid number for color value

(onboard:5711): Gtk-WARNING **: 18:16:57.249: Theme parsing error: colors.css:72:44: Invalid number for color value

(onboard:5711): Gtk-WARNING **: 18:16:57.249: Theme parsing error: colors.css:74:53: Invalid number for color value

(onboard:5711): Gtk-WARNING **: 18:16:57.249: Theme parsing error: colors.css:75:53: Invalid number for color value

(onboard:5711): Gtk-WARNING **: 18:16:57.249: Theme parsing error: colors.css:76:56: Invalid number for color value

(onboard:5711): Gtk-WARNING **: 18:16:57.249: Theme parsing error: colors.css:77:65: Invalid number for color value

(onboard:5711): dbind-WARNING **: 18:16:57.313: Couldn't connect to accessibility bus: Failed to connect to socket /tmp/dbus-45Zncq8Deu: В соединении отказано

(onboard:5711): dbind-ERROR **: 18:16:57.313: AT-SPI: Couldn't connect to accessibility bus. Is at-spi-bus-launcher running?
Ловушка трассировки/останова
Помогает:
user@host-184$ systemctl --user start at-spi-dbus-bus

При следующей загрузки системы ошибка повторяется.