unity - Can't log to my Ubuntu session after power failure

I'm getting this error when I try to log in to my Ubuntu session:

Your session only lasted less than 10 seconds. If you have not logged
out yourself, this could mean that there is some installation problem
or that you may be out of diskspace. Try logging in with one of the
failsafe sessions to see if you can fix this problem

Try in a terminal to run this command: :

mv ~/.config ~/.config-old

Then logging out and logging back in.

Or, maybe this post can be helpful for you.