Solution 1:

I was having the same problem although a slight difference was I installed in Virtual Box. When ask during the install for a admin/root password I created one. After the install and reboot I was ask for a user/other and password in order to log in. root and toor were not working After several failed tries I finally logged in using root as the user and the password I created during setup. Hope this helps someone.

Solution 2:

This worked for me:

  1. Select Other user

  2. Use root as the username

  3. Enter the root administrator password you entered during the install.

Solution 3:

Don't Worry...!

STEP 1: Wait till GRUB LOADER and SELECT (RECOVERY MODE) and hit e to EDIT...

STEP 2: Add this line as below -> init=/bin/bash enter image description here

Step 3: Then PRESS Ctrl+X or F10 to BOOT....

Step 4: After booted, TYPE fdisk -l which will display the partitions (the one with the * is root partition) as below:
enter image description here

Step 5: NOW, TYPE mount -o remount,rw /dev/sda1 /

Step 6: NOW, TYPE the passwd command to complete the password reset!!! and (exit or restart your system / in VirtualBox press Host key+R to reset the system)

Now you can log in with your new password!