I have added Transmission PPA. After adding PPA, when I tried to open software updater I got the following messege.

Failed to load the package list

This is a serious problem. Try again later. If this problem appears again, please report an error to the developers.

Even I could'nt open software sources, ubuntu software center, and sypnatic package manager.

What I have to do. Is there any command to remove the PPA.


The following command removes the ppa.

$ sudo add-apt-repository --remove ppa:PPANAME
$ sudo apt-get update
  • Thank you but still I am getting the following message:E:Encountered a section with no Package: header, E:Problem with MergeList /var/lib/apt/lists/ppa.launchpad.net_atareao_atareao_ubuntu_dists_quantal_main_i18n_Translation-en, E:The package lists or status file could not be parsed or opened. – Ashok Jun 28 '13 at 18:24

The answer from Sagar Rakshe is correct.
Here I explain how to perform it manually.

Remove the repository

First, identify your wrong file in /etc/apt/sources.list.d
(you may also have to check the main file /etc/apt/sources.list)

cd /etc/apt/sources.list.d 
head *.list

Then, rename the file to disable it:

sudo mv  WRONGFILE.list  WRONGFILE.list.backup 

Or instead of renaming the file, create a backup directory and move the file there:

sudo mkdir             backup_on_date_YYYMMDD
sudo mv WRONGFILE.list backup_on_date_YYYMMDD

For your information, add-apt-repository is a python script adding or commenting lines in your *.list files. Personally I prefer to handle myself these operations in order to keep clear & secure *.list files.

Remove the package signing keys

Show the installed apt keys with apt-key list and find the key for the repo you want to remove, for example:

pub   2048R/5044912E 2010-02-11
uid                  Dropbox Automatic Signing Key <linux@dropbox.com>

You can then use sudo apt-key del 5044912E to remove this key.

  • 1
    this won't remove the repo signing keys. I'll edit your answer to include that info. – amc Jul 3 '13 at 22:27

The graphical way of removing ppa repositories is as follows:

  • open your System Settings
  • click on the Softare & Updates icon
  • go to the Other Software tab
  • select the repository you want to remove
  • click the Remove button

I hope this helps

  • Again, this won't remove the signing keys. You can remove them using the graphical interface too -- under the Authetication tab in the Software Sources. – amc Jul 4 '13 at 16:07

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