update and package manager problems

[joe at actionline.com]

More often than not, Linux updates give me no end of problems.

My system is Mint 13

$ inxi -S
System: Host: leno Kernel: 3.2.0-23-generic i686 (32 bit) Desktop: KDE
4.8.3 Distro: Linux Mint 13 Maya

While I had done regular updates when alerted to do so, the last time, I
got ERROR messages reading:

W:Failed to fetch http://packages.medibuntu.org ... something wicked.

(and several more similar error messages ... but I was unable to
CTRL+A CTRL+C in the error message field to capture the contents. Why?)

So I did: $ grep -ri medibuntu /etc/apt/ ... and got these results:

Binary file /etc/apt/trusted.gpg~ matches
/etc/apt/sources.list.d/medibuntu.list.save:## MEDIBUNTU REPOSITORIES
/etc/apt/sources.list.d/medibuntu.list.save:deb
http://packages.medibuntu.org/ precise free non-free
/etc/apt/sources.list.d/medibuntu.list:## MEDIBUNTU REPOSITORIES
/etc/apt/sources.list.d/medibuntu.list:deb http://packages.medibuntu.org/
precise free non-free
Binary file /etc/apt/trusted.gpg matches
grep: /etc/apt/trustdb.gpg: Permission denied

... but I don't understand your instructions (below).
Am I supposed to edit the /edit/apt/sources.list.d file
and delete each reference to medibuntu?
And then am I supposed to run "apt-get update"
and then try to run synaptic update again?

Why is all this necessary? Why doesn't Linux mint update the necessary
files and repositories without requiring all this extra fooling around
(which is definitely *not* user-friendly)?

And how can I be sure that doing all this will not (once again) royally
mess up yet another Linux system for me?

----------------------
Brian Cluff last wrote:
> Looks like you removed the package database that apt creates from a
> package repository entry.  All you need to do to get rid of a repository
> is to delete the config file for it out of the apt config at
> /etc/apt/sources.list.d/<a_file_in_here.list> or to remove the line from
> the config file at /etc/apt/sources.list.
>
> After you've done that, just run "apt-get update" and it will clean out
> all the repositories that don't exist anymore as well as update all the
> ones that still do.
>
> After that, symantic should start working again.