Unable to launch "cinnamon-session-cinnamon"

Solution 1:

From your description I think cinnamon package is not installed or cinnamon-session-cinnamon command deleted/removed.

Try this steps:

• Press CTRL-ALT-F1 to change to text mode and login with your user.
• Change user to root with su or sudo command.
• Check package and program:
  • Query Cinnamon packge is installed or not: dpkg -l cinnamon
    • If there is no reuslt, the package is not installed or deleted/removed, install package: apt install cinnamon
  • If package installed (there is result dpkg command), list command: ls -l /usr/bin/cinnamon-session-cinnamon
    • If there is no reuslt, the package is deleted/removed, reinstall it: apt reinstall cinnamon
• If there are results both of them commands check ls output again, you should see permissions like this: -rwxr-xr-x
  • If your permission is different, set it: chmod 755 /usr/bin/cinnamon-session-cinnamon
• Reboot your computer.

I hope it will help you.