I get the following error when trying to update versions. I have all other updates on my system. I have tried to remove all non-Ubuntu PPAs. I did notice that this error had been posted previously, but it looks like there was no solution. Thoughts???

Unit packagekit.socket does not exist, proceeding anyway.
Created symlink /run/systemd/system/packagekit.socket → /dev/null.
Created symlink /run/systemd/system/packagekit.service → /dev/null.
Error: GDBus.Error:org.freedesktop.systemd1.UnitMasked: Unit packagekit.service is masked.
Error: GDBus.Error:org.freedesktop.systemd1.UnitMasked: Unit packagekit.service is masked.
Error: GDBus.Error:org.freedesktop.systemd1.UnitMasked: Unit packagekit.service is masked.
Error: GDBus.Error:org.freedesktop.systemd1.UnitMasked: Unit packagekit.service is masked.
Error: GDBus.Error:org.freedesktop.systemd1.UnitMasked: Unit packagekit.service is masked.
Error: GDBus.Error:org.freedesktop.systemd1.UnitMasked: Unit packagekit.service is masked.
exitMainLoopMidFlight
None
Removed /run/systemd/system/packagekit.service.
Removed /run/systemd/system/packagekit.socket.