unable to login LinuxMint 18.1 preempt-rt linuxcnc

Since a couple minutes I am unable to log in to my linuxcnc computer. once it boots up I get an error message your session took less than 10 seconds...
initclt: connection to upstrt not possible. failed to connect syndemon: no process found
/etc/mdm/Xsession:Beginning session setup...
localuser:kor beeing added to access control list

I got no idea what I have to do or can do. I would really prefer not to reinstall everything.
yesterday i did am update everything except the linux system.

If you go into grub advanced options you should have

1. A non upstart option
2. An upstart option
3. A recovery option

Try the non upstart option

This brings the same result.
even the generic kernel which is a different linux version gives that error.
I really need some help. at least I want to save my linuxcnc configs.

You might be able to stick the drive in another PC as a second drive and get the config folder from it.

Your best bet would be trying either ubuntu or mint forums. It would appear the issue is to do with the update, not so much a linuxcnc issue.

Have you tried the recovery option ?

Even if you have to reinstall you can boot the live version of Mint and copy everything to a usb stick, then do a reinstall

Before you chose an option press TAB and see if there is init=/sbin/upstart part to the "linux" line