Ubuntu Update Manager is showing an error message

Question

The error message is as follows:

Could not initialize the package information
An unresolvable problem occurred while initializing the package information.
Please report this bug against the 'update-manager' package and include the following error message:
'E:Malformed line 57 in source list /etc/apt/sources.list (dist parse)'

Answer 1

This means that there is something wrong with line 57 in your sources file. We need to fix that.

First, open up a terminal. To do so, hit Ctrl+Alt+T. In the prompt, type the following

gksu gedit /etc/apt/sources.list

Enter your password when prompted. This command opens up the file sources.list in a text editor so we can edit it.

You need to go down to line 57. You don't have to count the lines, you can look at the bottom right corner where you can see Ln 1, Col 1. So go to line 57. Let's say it looks something like this:

deb http://extras.ubuntu.com/ubuntu main

You need to change it to look like this:

deb http://extras.ubuntu.com/ubuntu raring main

Notice the difference between them? The difference is the word raring. However, this word corresponds to the Ubuntu version you are running. So for example, if your Ubuntu version is Ubuntu 12.10, the word should be quantal. To know which word you're supposed to put, look at the other lines in the file, you'll find the word in all the other lines. Once you add the word in, hit Ctrl+S to save the file, and close the window.

Now go to the update manager and check if the problem is solved or not.