Cannot log into MAC OS X after rename the disk I tried to rename the hard drive of my Macbook from "Macintosh HD" to something else without the freaking space. However, after renaming it, many of my applications showed errors immediately and I stupidly restarted my computer. Right now, I cannot log in to my user account because of an error. Everything is blocked...

If someone can tell me how to change the harddrive name back without logging into my previous account, I will appreciate it a lot. It will save my life!

Thanks
You can't log into your account because the OS can't find your user directory.
You have to boot the computer keeping pressed command + R to enter the restoration/repair mode. Then go to the "Utilities" in the upper menu and enter "Terminal".

Type:
/usr/sbin/diskutil rename "oldname" "newname" where oldname is the name you assigned to the disk and newname should be "Macintosh HD".

If everything is OK you will receive a message informing that the disk was renamed and you can restart your computer and log into your account.