Problem might be due to encryption of home folder
while mint installation. So don't encrypt home folder.
To Create another user without encryption,
Press Ctrl Alt F2 on the login screen, Terminal will be opened. -> login and make a new user.sudo useradd -m username -s /bin/bash
<--your current usernamesudo passwd username
<---new username & its password
Type 'logout' to exit screen
After that, if you load to linux mate normally you will see all those error messages. After you press ok for last error message, From the desktop, press Ctrl+Alt+F2.
In the terminal, If asked, login using new username and password. Then just type startx -- :2
You can then load to your old linux desktop.
I got this trick from viewtopic.php?f=46&t=109522
when I searched that last error message in Google.