Lately whenever I run
sudo apt-get update
it gives me the following error after the 'reading database' step
W: Duplicate sources.list entry http://archive.canonical.com/ubuntu/ precise/partner amd64 Packages (/var/lib/apt/lists/archive.canonical.com_ubuntu_dists_precise_partner_binary-amd64_Packages) W: Duplicate sources.list entry http://archive.canonical.com/ubuntu/ precise/partner i386 Packages (/var/lib/apt/lists/archive.canonical.com_ubuntu_dists_precise_partner_binary-i386_Packages) W: You may want to run apt-get update to correct these problems
Well I have run apt-get update over and over again and nothing changed. I also tried the options
sudo apt-get update --fix-missing
sudo apt-get update -f
which are really the same thing I know, but nothing seems to help.