What is the "recovery" option in the grub menu?
Solution 1:
Recovery mode boots up with basic services and drops you to a command line as root. From there you can repair any problems that are preventing you from booting Ubuntu normally.
Using recovery mode requires a little experience with the command line.
Solution 2:
The recovery option boots to a text mode screen which allows you to do some maintenance tasks. This can be useful if you need to reset your password, or your hard disk needs checking, or perhaps to troubleshoot an issue with the graphics driver.