I forgot the root password on one of my Ubuntu machines so I followed recovery steps provided here: How do I reset a lost administrative password?. I was successful with
passwd username command - I no longer got the wrong password error message - but now, after logging in, the screen flashes black and then returns me back to the login screen.
Then I tried removing the password by modifying the
/etc/shadow file (by following other answer in the linked question). i was successful once again - when I'm logging in I'm not prompted for password, just need to click on log in. but the result is the same, the screen flashes black and the login screen appears.
there is a message on the black screen that reads:
* Cheking battery state... [OK] * Stopping System V runlevel compatibility [OK] mountall: Disconnected from Plymouth