FIX: Black screen at login for LMDE/Cinnamon

So, I installed a fresh copy of LMDE on a machine. Obviously, that will include doing an apt-get dist-upgrade to ensure every thing is all up to date.

After doing that, I restarted the box and got the Mint login screen, entered my password and got . . . . . a black screen with a mouse pointer and nothing else.

I couldn't find an answer on the Internet so eventually I took a punt and entered:

apt-get install cinnamon

and what would you know, Cinnamon wasn't installed at all. For some, the distribution upgrade had decided to remove Cinnamon altogether. After the install finished I rebooted and all was good again.