nVidia driver preventing logout Mint KDE 18.2

[Metal Mick]

Hi all,

I have a fresh install of Mint 18.2 KDE and it is going pretty well with no issues so far. Except...

I used the Driver Manager to install the nVidia drivers instead of the default, and while everything is still going well, I find that when I'm using the nVidia GPU, the logout screen accessed from the lower left-hand corner fails to display. When I'm on the Intel on-board GPU, all is fine. I have an Allienware 17R, dual-booting into Linux or Windows.

My use of the nVida GPU is infrequent, but when I do, I'd like to be able to shut down the machine in the "regular" way.

Can anyone suggest a solution to this?