then press 'Reload' then 'Mark All Upgrades' then 'Apply'
You will probably have to reboot to complete the install. After rebooting, my update-manager no longer stated that I had a Partial Upgrade. Instead, it just shows several packages that are greyed out and that I can not install and indicates there are no updates to install. I assume they are held back for some reason.
Fixed - sort of...
I installed synaptic
> sudo apt-get install synaptic
Then did a package update and install in synaptic
> sudo synaptic
then press 'Reload' then 'Mark All Upgrades' then 'Apply'
You will probably have to reboot to complete the install. After rebooting, my update-manager no longer stated that I had a Partial Upgrade. Instead, it just shows several packages that are greyed out and that I can not install and indicates there are no updates to install. I assume they are held back for some reason.