Macbook hangs at startup

How long have you left it at that point? Another user reports the same issue, but they left it for another 15-20 minutes and then another message appeared highlighting a disk failure.

Try creating a bootable back up on an external drive ASAP and test it. Then at your leisure investigate further, that is leaving it on the start up verbose message screen.

I personally would recommend using carbon copy cloner as it was quite useful, but super duper has a free mode that should work for you.

I finally found a solution. This happened to me again and I could not even get my computer to startup. I found this website for repairing your disk in single user mode. http://www.everythingmacintosh.com/tech-notes/repair-your-hard-disk-in-single-user-mode/

The solution is to run /sbin/fsck -fy in single user mode.