Linux mint 18 64-Bit session failed

In my case I had installed virtualbox-guest-x11 on the base box so I had messed up x11 drivers. So I was getting this error message on $HOME/.xsession-errors:

initctl: Unable to connect to Upstart: Failed to connect to socket /com/ubuntu/upstart: Connection refused syndaemon: no process found /etc/mdm/Xsession: Beginning session setup... localuser:raskolnikov being added to access control list

I removed the package and re-installed cinnamon.

aptitude remove virtualbox-guest-x11 -y aptitude install cinnamon -y

Restarted the box and it worked.

There seems to be a problem with the most recent update of virtualbox-guest-x11.

I'm running Mint 18 Sarah, Mate edition, and after that update (27 or 28 March 2018) I had lost most of my icons from my panel, could not use any GUI tools to look at my network or printers and could not launch many of my applications, including Chromium, Firefox, Thunderbird, Xreader and Synaptic. The unlaunchable applications would give no error messages when I tried launching them, regardless of whether I tried as myself or as root, from the GUI or from the terminal, with or without -v or -vv.

A member of a local Linux user group directed me to this board. I ran

sudo apt-get purge virtualbox-guest-x11

and everything returned to 'normal'. I did not even have to reinstall the Mate desktop.

I don't know what you have done, but one thing is confirmed that some files were missed, which cause xwindow can't start normally. The solution is reinstalling the xwindow to make up the missing files. Try Ctrl+Alt+F1 to open another shell, then

sudo apt-get install cinnamon
sudo reboot

until get the GUI start up. It takes minutes, be patient, good luck.