Also, mentioned in the Known Problems, from the release notes, mentioned in two places (in case anyone missed it);
http://blog.linuxmint.com/?p=1979Important info
Known problems
Changelog
Login and password for the live session
The Live session should log you in automatically. If it doesn’t, or if you need to login manually (for instance, to try out Cinnamon), you can use the following credentials:
For the username, type “mint”
For the password, if asked, just press Enter.
http://www.linuxmint.com/rel_debian.phpKnown problems in Linux Mint Debian
Login and password for the live session
The Live session should log you in automatically. If it doesn't, or if you need to login manually (for instance, to try out Cinnamon), you can use the following credentials:
For the username, type "mint"
For the password, if asked, just press Enter.