Hang in login screen after shutdown

[Pamredrume]

I have installed 10.10 yesterday, it works right with a little slow than old system. But when I open the MBP today, it's hang in login screen, just show a loading mouse icon, tap on user name not response. I try to reboot some times, just the same thing. I try to hold shift on startup, but the loading progress bar just longing to about 50% and not go on for more than 10 mins. How can I make the MBP work again?

 

[Jinuljt]

Have the same problem. Any help?

 

[Pamredrume]

no, I just reinstall 10.9 and find some applications not properly work, just like Finder, IDEA's applications and so on.

 

[Jinuljt]

no, I just reinstall 10.9 and find some applications not properly work, just like Finder, IDEA's applications and so on.

so do i.... finder not work, system preferences lock..