This guide will help gather information that would be useful when creating a single, new question at

• https://answers.launchpad.net/ubuntu/+source/apt/+addquestion

Please only create a NEW question at https://answers.launchpad.net/ubuntu if you do not have an open question about this issue yet. If you already have an open question at https://answers.launchpad.net/ubuntu then please add the Terminal output below to the thread which was previously opened.

In order to gather essential troubleshooting information about your apt-get or aptitude or synaptic package manager in Ubuntu, please follow this procedure.

Step 1 First install a supported version of Ubuntu

The only supported releases of Ubuntu are the ones that are NOT End of Life (EOL) in the following table:

https://wiki.ubuntu.com/Releases

Step 2 Switch to "Main Server" using Software Sources

First switch from the regional server (US, UK, Swiss, etc...) to the "Main Server" using the Software Sources window

You can open up the Software Sources window by running the Update Manager. If you are using the Gnome Classic desktop it can be found in the menu (System > Administration > Update Manager). If you are Using Unity click the top icon in the dash and search for "update manager". In the update manager click on the Settings button at the lower-left corner of the window, and entering your password if prompted to do so.

See here for details and a screenshot of the main tab of the Software Sources window:

Repositories/Ubuntu#Download_Server

If you are unable to start "Update Manager" or unable to access Software Sources or Ubuntu Software Center, please skip step 1 and step 2 and proceed to step 3.

Step 3 Disable all PPA repositories

Open "Ubuntu Software Center" - Edit Menu --- Select "Software Sources...", enter your password

Select tab "Other Software"

From the "Other Software" tab, disable all PPA repositories, leaving only the official Ubuntu repositories active. Enabling too many PPA repositories (which are non-official) can cause your package manager to become unstable. If you do decide to re-enable such a PPA repository, I strongly suggest only enabling ONE PPA repository at a time for stability reasons, not several at the same time.

Step 4 Close all open programs

VERY IMPORTANT! Please make sure to close all open programs, including all package managers like Synaptic, Update Manager, Software Center, Add/remove programs, etc ... No other package manager should be running while running the commands below.

Step 5 Enable unlimited scrolling in Terminal

Open a Command-line / Terminal console

In the Ubuntu Terminal console , make sure that unlimited scrolling is enabled:

• click on Edit > Profiles > "Default" profile > Scrolling. Choose "Unlimited" as scrolling option. Click Close and Close again.

If you are using the Gnome interface, open the Terminal console via "Applications->Accessories->Terminal"

If you are using the Unity interface, the easiest way to open the Terminal is to use the 'search' function on the dash. Or you can click on the 'More Apps' button, click on the 'See more results' by the installed section, and find it in that list of applications. A third way, available after you click on the 'More Apps' button, is to go to the search bar, and see that the far right end of it says 'All Applications'. You then click on that, and you'll see the full list. Then you can go to Accessories > Terminal after that.

So the methods in Unity are:

Press CTRL-ALT-T key combination.

Dash > Search for Terminal

Dash > More Apps > 'See More Results' > Terminal

Dash > More Apps > Accessories > Terminal

Step 6 List of Terminal commands to execute and send to Launchpad Answers forum

Please copy-paste the following commands one line at a time using Chromium or Firefox into the Linux Terminal.

Tip: If you have a wheel mouse or 3 button mouse you do not need to type commands into the Terminal. Highlight each command on the page using the mouse. Move your cursor anywhere in the Terminal and press the wheel or middle button. Automatic Copy and paste! No spelling mistakes! No Typos! No other errors!

ubuntu-support-status || ubuntu-security-status

cat /etc/dpkg/dpkg.cfg.d/multiarch

dpkg --print-foreign-architectures

sudo grep -R roxy /etc/apt/*

grep roxy  /etc/environment

echo $http_proxy

echo $ftp_proxy

grep roxy /etc/bash.bashrc

grep roxy ~/.bashrc

cat /etc/apt/apt.conf

sudo fuser -vvv /var/lib/dpkg/lock

sudo fuser -vvv /var/cache/apt/archives/lock

cat /etc/lsb-release

uname -a

sudo rm /var/lib/apt/lists/lock 

sudo rm  /var/cache/apt/archives/lock

sudo rm /var/lib/dpkg/lock

sudo cp -arf /var/lib/dpkg /var/lib/dpkg.backup

sudo mv /var/lib/dpkg/status /var/lib/dpkg/status-bad

sudo cp /var/lib/dpkg/status-old /var/lib/dpkg/status  || sudo cp /var/backups/dpkg.status.0 /var/lib/dpkg/status

sudo mv /var/lib/dpkg/available /var/lib/dpkg/available-bad

sudo cp /var/lib/dpkg/available-old /var/lib/dpkg/available

sudo rm -rf /var/lib/dpkg/updates/*

sudo rm -rf /var/lib/apt/lists

sudo rm /var/cache/apt/*.bin

sudo mkdir /var/lib/apt/lists

sudo mkdir /var/lib/apt/lists/partial

LANG=C;sudo apt-get clean

LANG=C;sudo apt-get autoclean

sudo dpkg --configure -a

sudo dpkg --clear-avail

LANG=C;sudo apt-get -f install

LANG=C;sudo apt-get --fix-missing install

LANG=C;sudo apt-get --purge autoremove

LANG=C;sudo apt-get --fix-missing update -o APT::Cache-Limit=100000000

LANG=C;sudo apt-get update -o APT::Cache-Limit=100000000 && sudo apt-get dist-upgrade

find /etc/apt -name '*.list' -exec bash -c 'echo -e "\n$1\n"; cat -n "$1"' _ '{}' \;

sudo dpkg --audit

Step 7 Please send us the Terminal output

Please do NOT attempt to send any attachment(s). Please copy/paste the full terminal output of the previous list of diagnostic commands at this location: https://answers.launchpad.net/ubuntu/+source/apt/+addquestion

Please only create a NEW question at https://answers.launchpad.net/ubuntu if you do not have an open question about this issue yet. If you already have an open question at https://answers.launchpad.net/ubuntu then please add the Terminal output below to the thread which was previously opened.

The troubleshooters at Launchpad need to see the full Terminal output from running the previous list of diagnostic commands.

Step 8 Error occurs while trying to remove or upgrade a specific software package

If a package manager error occurs while trying to remove or upgrade a specific software package, please try the following workaround procedures:

http://askubuntu.com/questions/91543/apt-get-update-fails-to-fetch-files-temporary-failure-resolving-error

http://aziest.wordpress.com/2011/01/24/how-to-increase-your-apt-cache-limit/

http://www.cyberciti.biz/tips/troubleshooting-debian-ubuntu-package-upgrades-removals.html

http://www.ubuntugeek.com/package-installation-error-and-solution.html

The troubleshooters at Launchpad need to see the full Terminal output from running the above command.

If the previous apt-get update command returned any "404 Not Found" errors for certain Launchpad PPA's, then please open Software Sources via dash or System Settings and unmark/deactivate those failed Launchpad PPA's in Software Sources.

Step 9

If you are using the 64-bit edition of Ubuntu and if you are still encountering issues when trying to install certain Ubuntu packages, I suggest executing the following commands:

sudo dpkg --add-architecture i386

sudo apt-get update

Step 10 Ubuntu Software Center fails to open

If the Ubuntu Software Center fails to open, then please execute these Terminal commands:

killall -v gnome-software

sudo rm /usr/lib/python*/dist-packages/__pycache__/*pyc

sudo apt-get install --reinstall python3-gi

sudo apt-get purge software-center gnome-software

rm -rf ~/.cache/software-center

rm -rf ~/.config/software-center

rm -rf ~/.cache/update-manager-core

rm ~/.local/share/gnome-software/*

sudo rm /var/lib/apt-xapian-index/cataloged_times.p

sudo rm /var/lib/apt-xapian-index/values

sudo update-apt-xapian-index --verbose --force

sudo update-apt-xapian-index --force

sudo apt-get update

sudo apt-get dist-upgrade

sudo apt-get install software-center gnome-software

sudo dpkg-reconfigure software-center --force

sudo update-software-center

sudo apt-get install --reinstall software-center gnome-software

Then reboot and retest.

Sources:

https://bugs.launchpad.net/ubuntu/+source/software-center/?field.searchtext=&orderby=-importance&field.status%3Alist=CONFIRMED&field.status%3Alist=TRIAGED&assignee_option=any&field.assignee=&field.bug_reporter=&field.bug_commenter=&field.subscriber=&field.tag=&field.tags_combinator=ANY&field.status_upstream-empty-marker=1&field.upstream_target=&field.has_cve.used=&field.omit_dupes.used=&field.omit_dupes=on&field.affects_me.used=&field.has_patch.used=&field.has_branches.used=&field.has_branches=on&field.has_no_branches.used=&field.has_no_branches=on&field.has_blueprints.used=&field.has_blueprints=on&field.has_no_blueprints.used=&field.has_no_blueprints=on&search=Search

http://ubuntuforums.org/showthread.php?t=2033381

http://askubuntu.com/questions/69034/software-center-will-not-open

https://answers.launchpad.net/ubuntu/+source/software-center/+question/219728

https://answers.launchpad.net/ubuntu/+source/update-manager/+question/213929

https://askubuntu.com/questions/853705/gnome-software-centre-crashes-in-ubuntu-16-04

Step 11 You are using a proxy server to connect to the Internet

If you are using a proxy server, please make sure the following changes have been made in Ubuntu:

1) put the following configuration lines in the /etc/bash.bashrc file:

export http_proxy=http://<username>:<password>@<proxy>:<port>/

export https_proxy=https://<username>:<password>@<proxy>:<port>/

export ftp_proxy=ftp://<username>:<password>@<proxy>:<port>/

but REPLACING the values for username, password, proxy and port number, of course.

You can edit the /etc/bash.bashrc file using this command:

gksudo gedit /etc/bash.bashrc

2) put the following configuration lines in the /etc/environment file:

http_proxy=http://<username>:<password>@<proxy>:<port>/

https_proxy=https://<username>:<password>@<proxy>:<port>/

ftp_proxy=ftp://<username>:<password>@<proxy>:<port>/

but REPLACING the values for username, password, proxy and port number, of course.

You can edit the /etc/environment file using this command:

gksudo gedit /etc/environment 

3) put the following configuration lines in a new /etc/apt/apt.conf.d/80proxy file:

Acquire::http::proxy "http://<username>:<password>@<proxy>:<port>/";

Acquire::ftp::proxy "ftp://<username>:<password>@<proxy>:<port>/";

Acquire::https::proxy "https://<username>:<password>@<proxy>:<port>/";

but REPLACING the values for username, password, proxy and port number, of course.

You can edit the /etc/apt/apt.conf.d/80proxy file using this command:

gksudo gedit /etc/apt/apt.conf.d/80proxy

More documentation about the apt-get package manager

http://www.binarytides.com/apt-get-tutorial-package-management-ubuntu-commandline/

http://www.tecmint.com/useful-basic-commands-of-apt-get-and-apt-cache-for-package-management/

http://www.tuxarena.com/intro/ubuntu001.php