I have upgraded my Ubuntu 11.10 to 12.04. I could not see "other" login option in the login screen. it shows only "Guest login" and "User login. The User Login ask only password and I had never entered in as User login so that I do not know about password of User login. My question is how to login as root from the login screen? how can I get "Other login" option to login as root or some other user? before asking this question I have tried the following:

1. try to add the `greeter-show-manual-login=true` line at the bottom of `/etc/lightdm/lightdm.conf` file as **Guest login** but i get access denied error.
2. i do not know the password of User login (ask only password while login) to purpose of adding above line.
3. from the **safe mode login**, i could login as **root** but i could not add the above line the **lightdm.conf** file . i got read only error so that i tried to change the permission to 777 like the following  `chmod 777 lightdm.conf` (while I am in the /etc/lightdm/ dir). but I got the error **the file marked as/is read only in the file system.**
4. In 11.10 version I have created 4 users. I can see that the users exist in 12.10 . so I am sure that the user accounts are not removed in upgrade process.

In short, I need Other login option on my login screen? how to get it?

Edited Question:
----------------

I have add the following line the `/etc/lightdm/lighdm.conf` file on *recovery mode*

```
greeter-show-manual-login=true

```

and I saved the file using `wq` command.

now my `/etc/lightdm/lighdm.conf` file looking as the following:

```
[SeatDefaults]
greeter-session=unity-greeter
user-session=ubuntu
greeter-show-manual-login=true

```

if I commit any mistake please correct me. For this problem I have wasted the two working day and all the works are in pending.