Cannot log in with correct password after installing VirtualBox and Genymotion and editing /etc/profile

Question

This is a rather bizarre problem that I am experiencing. My Ubuntu 14.10 does not let me log in despite proper password. Here is what happens:

I try to log into my machine by entering the password. The password gets accepted, my laptop screen blinks, and brings me back to the login screen.

After having tried this many times I tried Guest Session. When I click on login in guest session, the same story repeats itself.

The only thing different from yesterday (when I could properly log in) is that I installed virtual box and Genymotion for Android development. Also, I made a simple change to /etc/profile to have genymotion in my path.

How do I solve this?

Solution

Open the terminal using CTRL + ALT + F1 (or whatever key works for you).
While in your home directory, type the command cat .xsession-errors.

This will give you the error that is causing the login screen loop. In my case it was an error in the /etc/profile that I had edited last night.

Comments

[Socceroos]

If you have no easy way to copy/paste the output, the just do this: sudo apt-get install pastebinit && tail -50 /var/log/syslog | pastebinit

[Zanna]

OP said nothing about nvidia drivers though

[Anwar]

Whay was the error?

[An SO User]

@Anwar it was some PATH related issue. I had a stray space in the path so it broke.