Introduction
The task error: command ‘apt-get update’ failed: exit code 100 is a common problem for Linux users, especially those using Ubuntu or Debian-based systems.
This error appears when the system is unable to refresh package lists from repositories. It can stop software installations, updates, and even automated scripts.
In this guide, you will learn what this error means, why it happens, and how to fix it in simple and easy steps.
What Does Exit Code 100 Mean?
Exit code 100 means that the apt package manager encountered a serious issue while trying to update repository information. The system could not download, read, or verify package lists properly.
When you see task error: command ‘apt-get update’ failed: exit code 100, it usually means something is wrong with your network, repositories, package lists, or system configuration.
Why Task Error: Command ‘apt-get update’ Failed Happens
There are several reasons why this error appears. Understanding the cause makes it easier to fix.
Broken Repository Sources
If your repository list contains invalid or outdated entries, apt-get update will fail.
Internet Connectivity Issues
A slow, unstable, or blocked internet connection can stop apt from downloading packages.
Corrupted Package Lists
Old or damaged package list files can cause update failures.
Locked Package Manager
Sometimes another process is already using apt, which prevents updates.
Expired GPG Keys
If repository keys are expired or missing, apt-get update cannot verify packages.
How to Check Your Internet Connection
Before making system changes, confirm that your internet is working.
Try opening any website or pinging a public server. If your connection is unstable, fix that first. Many task error: command ‘apt-get update’ failed: exit code 100 issues are simply due to internet problems.
Clean and Refresh Package Lists
Corrupted package lists are one of the main causes of this error.
Steps to Clean Package Lists
- Remove old lists
- Recreate fresh package lists
- Try running apt-get update again
This refresh often fixes update failures quickly.
Fix Broken Packages
Broken or half-installed packages can block apt-get update.
Why Broken Packages Matter
They can create dependency loops that prevent apt from completing tasks.
What to Do
Use the system’s repair options to automatically fix broken packages and then retry the update.
Check and Edit Repository Sources
Incorrect repository entries are a major cause of task error: command ‘apt-get update’ failed: exit code 100.
What Are Repository Sources?
They tell your system where to download updates from. If any source is outdated or invalid, apt will fail.
How to Fix
- Open your sources list
- Remove unused or unofficial repositories
- Keep only trusted official ones
- Save changes and try updating again
Remove Package Manager Locks
If another process is using apt, you may see this error.
Why Locks Happen
Automatic system updates or background tasks may already be running.
Fixing Locks
- Check for running apt processes
- Stop them if they are stuck
- Remove leftover lock files
- Run apt-get update again
Fix GPG Key Errors
GPG keys verify that packages come from trusted sources.
What Happens When Keys Expire
Your system refuses to download packages from that source, causing the error.
Solution
Refresh or reinstall the required keys, then try updating again.
Check Disk Space
Low disk space can stop apt from saving package lists.
Why This Matters
If your system runs out of space, updates cannot complete.
What to Do
- Check free disk space
- Remove unused files
- Clear old packages
- Retry apt-get update
Fix DNS and Network Settings
Sometimes the error is caused by DNS problems.
Common Network Issues
- Wrong DNS servers
- Firewall blocking connections
- Proxy misconfiguration
Correcting these settings can instantly fix task error: command ‘apt-get update’ failed: exit code 100.
Restart Your System
A simple restart clears temporary issues, locked processes, and network glitches. Many users fix the error just by restarting.
Preventing apt-get Update Errors in the Future
Keep Your System Clean
Regularly remove old packages and clear cache files.
Avoid Untrusted Repositories
Only use well-known and official sources.
Update GPG Keys Periodically
This avoids verification failures.
Monitor Disk Space
Always keep some free storage available.
When to Reinstall Your Package Manager
If none of the solutions work, your apt package manager may be corrupted. Reinstalling it restores missing files and resets configurations.
Conclusion:
The task error: command ‘apt-get update’ failed: exit code 100 is a common but fixable Linux issue. It usually happens because of broken repositories, corrupted package lists, expired keys, network problems, or locked processes.
By cleaning your system, fixing broken packages, checking repositories, ensuring stable internet, and freeing disk space, you can solve this error easily and keep your system running smoothly.