[Fixed] “sudo apt update” Not Working Error in Ubuntu

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Linux users are well-acquainted with the command line, and one of the frequent employment commands is sudo apt update. This command is pivotal in ensuring your system remains current by retrieving the latest package details from software repositories. Nonetheless, there can be instances when you face difficulties with the sudo apt update not working as anticipated. In this article, we will investigate the typical causes of this issue and offer remedies to restore your system’s proper functioning.

Key Takeaways

  • Investigating different factors contributing to the malfunction of the sudo apt update command.
  • Acquiring knowledge of the solutions to restore the proper functionality of the sudo apt update command.


  • To resolve the issues, you must have root privilege as you may need to change files or repositories related to ‘apt’.

Understanding the “sudo apt update” Command

The sudo apt update in Linux refreshes the software package list from online repositories to keep your system informed about software versions and dependencies, which is essential for installing, upgrading, and maintaining packages. It’s a crucial task for both system security and software management.

Causes of Errors With “sudo apt update” Command

The sudo apt update command may encounter various issues leading to failure, usually accompanied by error messages that provide insights into the root cause. Here, we’ll explore typical reasons for the malfunctions of ‘sudo apt update’.

  • Internet Connection Issues
  • Repository Configuration Errors
  • Software Conflicts
  • Proxy Settings
  • Firewall or Security settings
  • Outdated Package Manager
  • Inconsistent Package Lists.

Solutions to 3 Types of “sudo apt update” Not Working Error in Ubuntu

While running the command sudo apt update, Linux users may sometimes fall into trouble for a couple of reasons. It normally generates error messages rather than updating the packages of the Linux system.

A. Fixing “sudo apt update” GPG Errors

When you execute the sudo apt update command and come across the ‘gpg error’, it usually signals a problem with the GPG (GNU Privacy Guard) key responsible for confirming the authenticity of software packages within your package manager’s repository. This issue can impede your ability to update your package lists and install or upgrade software packages.

While trying to update my packages, the GPG error hinders the operation as you can notice from the picture. The error message includes the repository and mentions that the public key is unavailable. This problem can occur for multiple reasons. To resolve the problem you can follow the steps below.Shows GPG error while running 'sudo apt update' command.Steps to Follow >

➊ Open a terminal on Ubuntu.

➋ Run the following command to open the file /etc/apt/sources.list

sudo nano /etc/apt/sources.list
  • sudo: Provides the root privilege to perform the administrative command.
  • nano: Opens files in CLI and allows you to edit the file like a text editor including multiple features.
  • /etc/apt/sources.list: contains a list of software repositories or sources from which the apt package manager retrieves and installs software packages.

Opens the sources.list file with nano command.➌ Enter the user password and the file will be opened.Shows the file's content which needs to modify. As the file opened, I searched for the line ‘deb https://pkg.jenkins.io/debian binary/,’ which configures an APT repository for Jenkins. Jenkins is a widely used automation server that plays a crucial role in building, deploying, and automating software projects.

Remove the marked line or use a hash ‘#’ icon in front of the line to comment out the line.

➎ Now, run the command sudo apt update again and update your system packages.sudo apt update command works properly after solving the GPG error Now, here you can see the result of the sudo apt update command as you’ve anticipated.

B. The Repository Doesn’t Have Release File (404 Not Found (IP))

Linux users may face this error when apt is unable to find or access the release file for a repository. This file contains important metadata about the repository including information about the available packages, their versions, and more.Shows '404 not found' or 'repository doesn't have release file' error while running sudo apt update command. Here, you can see that the ‘https://ppa.launchpadcontent.net/deadsnakes/ppa/ubuntu lunar Release’ repository does not have any release file in my Ubuntu.

In case of a missing release file of any repository, you can resolve the erroneous situation from both GUI and CLI. Here’s how to address this issue described below.

You can read our Comparative Analysis of Methods to distinguish between these two methods and pick the best one for your needs.

Method 01: Using GUI to Fix 404 Not Found [IP…] Error in Ubuntu

It’s so simple to avoid this error just by using your GUI.

Steps to Follow >

➊ Open the Menu bar, and find the software and updates from the search bar.Searches the 'Software & Updates' application from the search bar of the menu.➋ Finally run the ‘software & Updates’ application.Opens the "software & Update' application after running it.➌ Now, click on the ‘other software’ option.Shows the list of other repository files.Uncheck the repository. Immediately a prompt will appear asking for the user password to authenticate.

➎ Provide the user password.Asks for user password to authenticate identity.➏ Lastly, close the ‘Software & Updates’ application and again run the sudo apt update command.Shows a successful update operation. Here you can see that the sudo apt update is working properly.

Method 02: Using CLI to Fix 404 Not Found [IP…] Error in Ubuntu

You can also address the ‘404 not found’ issue by utilizing the command-line interface (CLI).

Steps to Follow >

➊ Open the Ubuntu terminal.

➋ Run the following command.

sudo add-apt-repository –remove ppa:deadsnakes/ppa
  • sudo: Gives the permission to execute commands with superuser (root) privilege.
  • add-apt-repository: Used to manage APT repositories specifically to add new repositories.
  • –remove: This option tells ‘add-apt-repository’ to remove the mentioned repository in the command rather than add it.
  • ppa:deadsnakes/ppa: Refers to a PPA maintained by the deadsnakes team which provides updated Python packages and I want to remove it.

Removes the repository whose release file is missing using sudo add command➌ Now, to recheck whether it’s working or not, run the sudo apt update command.Shows the 'sudo apt update not working' problem is resolved. The sudo apt update command is working accordingly after all the necessary modification is done.

C. The List of the Sources Could Not Be Reached

Another one of the simplest problems may occur while running the sudo apt update command that you can see below in the picture.Shows errors mentioning that sudo apt update could not get lock directory. This issue tends to arise, particularly when ‘apt’ is engaged in another task, such as updating or installing software.

To get out of this issue, ensure that your apt package manager is completely available for the update process. For this, you can check whether any software is currently installing or updating or not. Whenever the process is finished, you can run the sudo apt update command.

Comparative Analysis of Methods to Solve 404 Not Found (IP) Error

I’ve presented two methods for troubleshooting when the repository release file doesn’t exist (404 not found error). It can be challenging to determine which one is the most suitable for your needs. To help you make an informed decision, here’s a comparison of the provided methods, outlining their pros and cons.

Methods Pros Cons
Method 1
  • It’s more convenient and reliable to use GUI as it’s manual.
  • The chances of making mistakes are less.
  • It demands a greater amount of time.
  • Comparatively complex due to its inclusion of several steps.
Method 2
  • Using CLI to resolve the error is just a one-command operation.
  • Simpler and time-efficient due to its one-step troubleshooting.
  • Needs to be careful while specifying the repository in the mentioned format.

While choosing any one method, you can consider your situation and expertise. If you are an expert in using CLI commands and can maintain the specific format of Commands then go for Method 2 certainly. Otherwise, you can choose Method 01 as it is manual and less sensitive than CLI and does not require much attention.


In a nutshell, sudo apt update is an essential command to preserve the stability, security, and performance of your Linux system based on Debian. Consistently refreshing your package information guarantees that your system remains current with the most recent software and security updates. Then again, you may also face some unexpected results hindering your update operation. But, no worries there is a solution to fix that some of which I’ve tried to present in this article. Hope this has made your trouble quite easier to fix.

People Also Ask

How do I fix apt update problems in Linux?
To resolve ‘apt update’ problems in Linux, review and rectify any errors in your repository URLs within /etc/apt/sources.list or /etc/apt/sources.list.d/ and then re-run ‘sudo apt update’ to update your package information.
How do I enable sudo apt update?
To execute ‘sudo apt update’ on Linux, open a terminal, input the command, and supply your administrative password if requested. This action will refresh package lists.
What is apt install?
The ‘apt install’ command is used to install software packages on a Debian-based Linux system that allows users to specify the name of the package they want to install along with its dependencies from the configured software repositories.
How do I fix apt?
To reset ‘apt’ in Linux, First run ‘sudo apt clean’ to clear the local package cache. Next, execute ‘sudo rm -rf /var/lib/apt/lists/*’ to delete cached package lists. Finally, run ‘sudo apt update’ to refresh the package lists.

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Auhona Islam

Auhona Islam is a dedicated professional with a background in Electronics and Communication Engineering (ECE) from Khulna University of Engineering & Technology. Graduating in 2023, Auhona is currently excelling in her role as a Linux content developer executive at SOFTEKO to provide a more straightforward route for Linux users. She aims to generate compelling materials for Linux users with her knowledge and skills. She holds her enthusiasm in the realm of Machine Learning (ML), Deep Learning (DL), and Artificial Intelligence (AI). Apart from these, she has a passion for playing instruments and singing. Read Full Bio

2 thoughts on “[Fixed] “sudo apt update” Not Working Error in Ubuntu”

    • Usually the synaptic requires the root password that you set while installation. So use that root password for authentication. I don’t speak Hungary. But if you share your problem using any translator I can help you .


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