Here is the error I get trying to open ubuntu-software (which points to gnome-software):
$ ubuntu-software
(ubuntu-software:6610): Gs-WARNING **: Failed to create permission org.freedesktop.packagekit.trigger-offline-update: GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: Action org.freedesktop.packagekit.trigger-offline-update is not registered
(ubuntu-software:6610): Gs-WARNING **: Failed to create permission org.freedesktop.packagekit.trigger-offline-update: GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: Action org.freedesktop.packagekit.trigger-offline-update is not registered
(ubuntu-software:6610): Gs-WARNING **: Failed to create permission org.freedesktop.packagekit.trigger-offline-update: GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: Action org.freedesktop.packagekit.trigger-offline-update is not registered
(ubuntu-software:6610): Gs-WARNING **: Failed to create permission org.freedesktop.packagekit.trigger-offline-update: GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: Action org.freedesktop.packagekit.trigger-offline-update is not registered
(ubuntu-software:6610): Gs-WARNING **: Failed to create permission org.freedesktop.packagekit.trigger-offline-update: GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: Action org.freedesktop.packagekit.trigger-offline-update is not registered
(ubuntu-software:6610): Gtk-WARNING **: Error loading image 'file:///usr/share/gnome-software/featured-inkscape.png': Error opening file: Too many open files
(ubuntu-software:6610): GLib-ERROR **: Creating pipes for GWakeup: Too many open files
Similar bug posted on http:// askubuntu. com/q/855522/ 135465.
Here is the error I get trying to open ubuntu-software (which points to gnome-software):
$ ubuntu-software
(ubuntu- software: 6610): Gs-WARNING **: Failed to create permission org.freedesktop .packagekit. trigger- offline- update: GDBus.Error: org.freedesktop .PolicyKit1. Error.Failed: Action org.freedesktop .packagekit. trigger- offline- update is not registered
(ubuntu- software: 6610): Gs-WARNING **: Failed to create permission org.freedesktop .packagekit. trigger- offline- update: GDBus.Error: org.freedesktop .PolicyKit1. Error.Failed: Action org.freedesktop .packagekit. trigger- offline- update is not registered
(ubuntu- software: 6610): Gs-WARNING **: Failed to create permission org.freedesktop .packagekit. trigger- offline- update: GDBus.Error: org.freedesktop .PolicyKit1. Error.Failed: Action org.freedesktop .packagekit. trigger- offline- update is not registered
(ubuntu- software: 6610): Gs-WARNING **: Failed to create permission org.freedesktop .packagekit. trigger- offline- update: GDBus.Error: org.freedesktop .PolicyKit1. Error.Failed: Action org.freedesktop .packagekit. trigger- offline- update is not registered
(ubuntu- software: 6610): Gs-WARNING **: Failed to create permission org.freedesktop .packagekit. trigger- offline- update: GDBus.Error: org.freedesktop .PolicyKit1. Error.Failed: Action org.freedesktop .packagekit. trigger- offline- update is not registered
(ubuntu- software: 6610): GLib-CRITICAL **: g_dir_read_name: assertion 'dir != NULL' failed
(ubuntu- software: 6610): Gtk-WARNING **: Error loading image 'file:/ //usr/share/ gnome-software/ featured- inkscape. png': Error opening file: Too many open files
(ubuntu- software: 6610): GLib-ERROR **: Creating pipes for GWakeup: Too many open files
Trace/breakpoint trap (core dumped)