raspberry pi using vnc, can't log in.

Last night, when i was using vnc to log in my ras pi, i found that i stuck in the login menu.

which means even i type the correct password, after several sec, it going back to the login menu.

So, it turns out vnc may have some authoritive problem. WE can simply solve this problem by log in the ssh use:

rm -rf /home/pi/.Xauthority