How to Safely Upgrade Ubuntu: Step-by-Step Guide for Beginners and Advanced Users

By 佐川 直弘 | Naohiro Sagawa (運営者)

※記事内に広告を含みます。Amazonアソシエイトとして適格販売により収入を得ています。　

1. Preparing Before the Upgrade

Before upgrading Ubuntu, it’s crucial to take several important steps. Skipping them can lead to problems during the upgrade process or increase the risk of data loss. This section outlines basic steps to help ensure system stability and safety.

Backups Are Essential

Although Ubuntu upgrades are generally safe, creating a backup in advance is essential in case something goes wrong or unexpected errors occur.

There are a few ways to back up your data. The following options are simple and beginner-friendly:

• Copy important files to an external HDD or USB flash drive
• Use the rsync command to back up your entire home directory
• Use image backup tools like Clonezilla

Here’s an example of how to perform a backup via command line:

rsync -a --progress /home/your-username /media/backup-drive/

Make sure your data is fully protected before proceeding with the upgrade.

Update Your System First

To ensure a smooth upgrade, your current Ubuntu system should be fully updated. Run the following commands to update all installed packages:

sudo apt update
sudo apt upgrade
sudo apt dist-upgrade

dist-upgrade is especially important because it handles upgrades involving changes in dependencies.

Remove Unnecessary Packages

Leftover packages can cause errors during the upgrade. Clean up your system using the following command:

sudo apt autoremove

It’s also a good idea to clear the package cache to free up disk space and improve upgrade reliability:

sudo apt clean

These are the essential steps you should take before upgrading Ubuntu. By backing up your data and maintaining your system properly, you can upgrade with peace of mind.

2. How to Upgrade Ubuntu

There are two main ways to upgrade Ubuntu: using the GUI (Graphical User Interface) or using the command line (Terminal). This section explains both methods step by step, along with helpful tips.

Upgrading via GUI (Recommended for Beginners)

If you’re using the desktop version of Ubuntu, the GUI upgrade method is the most user-friendly and stress-free option.

Step 1: Check Your Settings

First, open “Software & Updates” and go to the “Updates” tab. Make sure that “Notify me of a new Ubuntu version” is set to “For any new version” or “For long-term support versions.”

Step 2: Launch the Update Manager

Open “Software Updater.” If a new version is available, you’ll see a notification.

Note: If you’re upgrading from one LTS (Long Term Support) version to the next, the upgrade may only appear after the first point release (e.g., 22.04.1).

Step 3: Proceed with the Upgrade

Click the “Upgrade” button when prompted, and follow the on-screen instructions. You’ll be asked to confirm several steps, so review them carefully. Make sure your computer stays powered on throughout the process.

Upgrading via Command Line (For Intermediate to Advanced Users)

For server environments or those who want more control over the process, upgrading via command line is the preferred method.

Step 1: Install Required Packages

Make sure the upgrade tool is installed. Run the following command just in case:

sudo apt install update-manager-core

Step 2: Check the Configuration File

Open the /etc/update-manager/release-upgrades file and check the value of Prompt= as follows:

• For regular (non-LTS) releases: Prompt=normal
• For LTS releases only: Prompt=lts

sudo nano /etc/update-manager/release-upgrades

Step 3: Start the Upgrade

Run the following command to begin the upgrade process:

sudo do-release-upgrade

This command will upgrade your current Ubuntu version to the next available one. You may be asked to confirm several prompts, so read each message carefully.

Tip: If you’re upgrading over SSH (e.g., on a server), consider using the -d or -f DistUpgradeViewNonInteractive options.

Whether using the GUI or the command line, the upgrade usually takes around 30 minutes to 1 hour depending on your system. You may be prompted to reboot after the process is complete.

3. Important Notes During the Upgrade

Upgrading Ubuntu is generally a safe process, but there’s always a chance that something unexpected might occur. This section covers common issues during upgrades, how to deal with them, and tips for making the right decisions when prompted.

How to Handle Error Messages

During the upgrade, you might encounter error messages like the ones below.

Example 1: “Unable to fetch some archives, maybe run apt-get update or try with –fix-missing?”

This error means that some packages couldn’t be downloaded. Try the following command:

sudo apt update --fix-missing

In most cases, the upgrade can proceed successfully after trying again.

Example 2: “dpkg was interrupted, you must manually run ‘sudo dpkg –configure -a'”

This indicates that the installation process was interrupted. Try to recover using this command:

sudo dpkg --configure -a

Then, re-run sudo apt upgrade to verify that everything is in order.

Choosing What to Do with Configuration Files

During the upgrade, you may be asked whether to replace configuration files (such as /etc/default/grub or /etc/ssh/sshd_config) with newer versions.

You’ll typically see the following options:

• Keep the current version
• Install the new version
• Compare both versions (press d to view the diff)

Which Option Should You Choose?

• If you haven’t made any custom changes → Install the new version
• If you’ve made specific changes → Keep the current version

That said, you can also manually compare and edit configuration files later. When in doubt, check the differences and make an informed choice.

Avoid Power or Network Issues During the Upgrade

If the power goes out or your internet connection drops during the upgrade, the process may stop midway, which can make your system unstable. This is especially important for laptop users. Take the following precautions:

• Keep your device plugged into a power source
• Ensure a stable internet connection
• Set aside enough time for the entire process without interruptions

By following these precautions, you can safely complete the Ubuntu upgrade process.

4. Post-Upgrade Checklist

Even if the Ubuntu upgrade completes successfully, it’s important to run a few checks and make some adjustments to ensure the system is stable and comfortable to use. This section outlines key steps to take after upgrading.

Check the System Version

First, verify that the upgrade was successful by checking the system information. Run the following command in the terminal:

lsb_release -a

Example output:

Distributor ID: Ubuntu
Description:    Ubuntu 24.04 LTS
Release:        24.04
Codename:       noble

If you see the intended version listed, your upgrade was successful.

Remove Unused Packages

After the upgrade, old packages and dependencies from the previous version may still remain. To free up space and improve stability, run the following commands to clean them up:

sudo apt autoremove
sudo apt clean

This removes unnecessary caches and unused libraries, helping to conserve disk space.

Check Japanese Input and Locale Settings

After upgrading, Japanese input (especially IBus or Fcitx) may not work correctly. If you’re unable to type in Japanese or if your input source is missing, follow these steps to reset it.

If using Fcitx:

sudo apt install fcitx-mozc
im-config -n fcitx

After logging out or rebooting, the input method should be enabled.

To reconfigure locale settings:

sudo dpkg-reconfigure locales

This can be helpful if the display language has reverted to English or another language unintentionally.

Check Third-Party Applications

Upgrading Ubuntu can sometimes affect the compatibility of PPAs (Personal Package Archives) or Snap apps. Check the following points:

• Ensure your frequently used applications are working properly
• Check whether PPAs were disabled during the upgrade (re-add them if needed)
• Make sure Snap apps are still set to auto-update

To re-enable PPAs, check the /etc/apt/sources.list.d/ directory and re-add or re-authenticate repositories as needed.

These are the key steps to take after upgrading Ubuntu. Once you’ve confirmed your system is working properly, you’re ready to resume everyday use with confidence.

5. Frequently Asked Questions (FAQ)

Here are some frequently asked questions and answers about upgrading Ubuntu. Whether you’re planning an upgrade or have already completed it, this section can help clear up common doubts.

Q1. How long does it take to upgrade Ubuntu?

A1. It depends on your environment and internet speed, but it typically takes about 30 minutes to 1 hour.
If you’re upgrading from an older version through multiple stages (e.g., 18.04 → 22.04) or using a low-performance machine, it may take longer. Be sure to allocate enough time in advance.

Q2. What should I do if the power goes out during the upgrade?

A2. A power outage can corrupt system files. Try the following steps first:

1. Boot into recovery mode (from GRUB, select “Advanced options” → “Recovery mode”)
2. Try to repair using the following commands:

sudo dpkg --configure -a
sudo apt update
sudo apt upgrade

3. If things are too broken, restore from a backup or use a Live USB to recover your data.

Q3. What’s the difference between an LTS version and a regular version?

A3. LTS (Long Term Support) versions receive updates for 5 years and focus on stability and reliability. Regular (interim) versions introduce new features more quickly, but are only supported for 9 months.

• Who should use LTS: Server users, business environments, and those who prioritize system stability
• Who should use regular versions: Advanced users and developers who want the latest features

Q4. Can I upgrade directly from an old version to the latest one?

A4. No, you generally need to upgrade one version at a time. For example, you can’t go directly from 18.04 LTS to 22.04 LTS — you must go through 20.04 LTS first.
However, Ubuntu officially supports LTS-to-LTS upgrades, and in many cases, you can do this with do-release-upgrade.

Q5. If something goes wrong after upgrading, can I roll back?

A5. Unfortunately, Ubuntu does not have a built-in rollback feature like Windows. That’s why creating a backup beforehand is absolutely essential.
If you really need to go back, you’ll have to perform a clean install using the ISO of your previous version and restore your data from a backup.

These FAQs are based on real user experiences. Knowing the answers to common questions can help you upgrade with greater confidence and fewer surprises.