Edit: Some users are reporting being able to login but having problems with their panel instead (the taskbar if you will). Below workaround is suggested for them as well. This was confirmed to work by several users.
For users of Linux Mint 18.x not yet affected by either of above issues they should see an update for Update Manager (mintupdate). Installing that will do the same thing as below and remove the virtualbox-guest* packages from their system that appear to be the root cause of the issues.
If you are affected by either of above issue we suggest you do either of these to recover:
- You can manually do the same thing that Update Manager would have done for you with these steps:
- From the login screen press Ctrl+Alt+F1 to go to a virtual console (full screen terminal);
- Login as yourself (you get no visual feedback as you type passwords, just type it and press Enter);
- Then run this command:
apt remove virtualbox-guest*
- After the command completes you can return to the login screen by pressing Ctrl+Alt+F7 or F8 and then reboot your system.
- If you have Timeshift installed and configured, and are comfortable with it, you can alternatively use that to roll back your operating system to an earlier snapshot. Then install available updates from Update Manager will also fix this issue.