Kubuntu Focus: Installation Recovery Guided Solution

Installation Recovery

Recover a Kubuntu Focus System

All general purpose OSes (Windows, MacOS, Linux) can be changed so that the system will no longer boot completely or will behave strangely. A corrupt or full system disk, broken software packages, misconfiguration, and many other situations can cause this. Read on to find how you can use FocusRx and other tools to recover a system.

Limitations
System Rollback
Rollback Packages
Rollback Repositories
Recover from BusyBox Shell
Fix Your System Using FocusRx
Reset a User Password
Use a Live USB for Recovery
24.04 LTS (Noble): Use chroot to Recover a System
22.04 LTS (Jammy): Use chroot to Recover a System
Revisions
Disclaimer

Recover your system with multiple techniques.

Please read the disclaimer before proceeding. We review and update guided solutions regularly. If you have suggestions or requests, please write support@kfocus.org.

Limitations

Before you proceed, first determine if this is actually a system issue. If your system boots fine, this is likely an application issue. We recommend you first visit the Focus Support page and search for a topic using the list or the search box. These are almost always more current and correct for your hardware than HOWTOs or forum posts you might find on the web. You should continue here only if your system does not completely boot or if you are getting warnings about missing dependencies or libraries.

Recovering an installation may be preferable because applications, settings, and other data will not need to be restored. However, like with all OSes, a badly broken system can take hours to recover and still be problematic. While a Clean Install requires recovery of data, it usually takes well under 30 minutes and can solve issues you do not have time to research or understand. For these reasons, we recommend you always keep a clean installation as an alternative and limit the time you dedicate to recovery efforts.

Any system work always has inherent risks. Mistakes happen, and in this context, that can mean data loss. It is important, therefore, to keep your data safe using a backup solution on an external disk. See the Backups Guided Solution to save your data before proceeding if possible.

System Rollback

System Rollback is available on systems that run Kubuntu 24.04 LTS with KFS and use the default or recommended BTRFS filesystem. It is not available for other filesystems or prior versions of Kubuntu. Use it to create and restore coherent system snapshots. This is useful for recovering from failed software installation or updates. See the System Rollback Guided Solution to learn how to create and manage snapshots.

Open System Rollback

You can control System Rollback using the System Rollback Dashboard. You can launch the dashboard in one of two ways - either through Start Menu > Kubuntu Focus Tools > System Rollback Dashboard, or by clicking the System Rollback icon in the system tray. If neither of these items exists, the system does not support System Rollback.

Restore a Snapshot

1. Launch the System Rollback Dashboard as described above.

2. Select the snapshot you wish to restore from the left-hand sidebar, then click [ Restore ].

Choose the snapshot you wish to restore, then click 'Restore'.

3. Ensure that you save all open work on the system, then click [ Restore ] again to restore the snapshot. It will prompt you for your password. Once you have authenticated, the system will reboot.

Save open work, then confirm snapshot restoration.

4. It will show confirmation that the rollback was successful once you have logged in again. Click [ OK ] to dismiss the notice, or click [ More Info ] for guidance on how to compare the system's restored state to its previous state.

Rollback Packages

Sometimes the latest version of a package has a bug or missing feature you find unacceptable. When this happens, you can specify a package version, or install a debian package from the archive. Here is an example of a package rollback of FileZilla:

Specify a package version

We can use apt-cache policy to find an older version of a package:

# Find available versions apt-cache policy filezilla #> filezilla: #> Installed: 3.58.0-1ubuntu0.1 #> Candidate: 3.58.0-1ubuntu0.1 #> Version table: #> *** 3.58.0-1ubuntu0.1 500 #> 500 http://us.archive.ubuntu.com/ubuntu jammy-updates/universe amd64 Packages #> 500 http://security.ubuntu.com/ubuntu jammy-security/universe amd64 Packages #> 100 /var/lib/dpkg/status #> 3.58.0-1 500 #> 500 http://us.archive.ubuntu.com/ubuntu jammy/universe amd64 Packages

We can use this knowledge to install and hold the earlier version. Notice how we included filezilla-common too, as we discovered this dependency also needed a rollback:

# Install older versions sudo apt install filezilla=3.58.0-1 filezilla-common=3.58.0-1 # Mark hold to prevent an upgrade sudo apt-mark hold filezilla filezilla-common # Show held files sudo apt-mark showhold # Remove holds sudo apt-mark unhold filezilla filezilla-common # Upgrade to latest sudo apt full-upgrade

Install a debian package from the archive

Older versions of packages are not always available from a repository. For example, google-chrome-stable does not always show as having an earlier available version. However, you can find and downgrade to an earlier version using the local archives.

# Find cached packages ls /var/cache/apt/archives \ |grep -E '^google-chrome-stable*' |sort -V #> google-chrome-stable_120.0.6099.216-1_amd64.deb #> google-chrome-stable_121.0.6167.184-1_amd64.deb #> google-chrome-stable_122.0.6261.111-1_amd64.deb # Install desired version cd /var/cache/apt/archives sudo apt install ./google-chrome-stable_121.0.6167.184-1_amd64.deb # Mark hold to prevent upgrade sudo apt-mark hold google-chrome-stable # Show held files sudo apt-mark showhold # Remove holds sudo apt-mark unhold google-chrome-stable # Upgrade to latest sudo apt full-upgrade

Make sure to check and remove holds regularly. Out-of-date packages can cause incompatibilities and even prevent other packages from installing correctly, so do this with care.

Rollback Repositories

Sometimes you just want to get rid of all packages and dependencies that come from a repository. ppa-purge is excellent for this purpose:

# Add a repository to /etc/apt/sources-list.d sudo add-apt-repository ppa:jonathonf/ffmpeg-4 # Disable repo but keep packages from it sudo add-apt-repository --remove ppa:jonathon/ffmpeg-4 # Re-enable it sudo add-apt-repository ppa:jonathonf/ffmpeg-4 # Purge all package from this repo sudo ppa-purge ppa:jonathonf/ffmpeg-4

ppa-purge downgrades packages to their previous versions, if possible, before the repository's addition. While designed for PPA repositories, ppa-purge can also handle most commercial third-party repositories. See ppa-purge -h for the switches used in the examples below:

# Inspect and remove Slack repo. This removes the slack app too! cat /etc/apt/sources.list.d/slack.list #> deb https://packagecloud.io/slacktechnologies/slack/debian/ jessie main # ppa-purge, preferring apt-get over aptitude sudo ppa-purge -i -s packagecloud.io -o slacktechnologies -p slack -d jessie

# Inspect and remove MongoDB repo cat /etc/apt/sources.list.d/mongodb-org-7.0.list #> deb [ arch=amd64,arm64 signed-by=/usr/share/keyrings/mongodb-server-7.0.gpg ] https://repo.mongodb.org/apt/ubuntu jammy/mongodb-org/7.0 multiverse # ppa-purge, preferring apt-get over aptitude sudo ppa-purge -i -s repo.mongodb.org -o apt -p ubuntu -d jammy

You can learn more with this Linuxize article.

Recover from BusyBox Shell

Sometimes the system will boot but drop to a BusyBox Shell as shown below.

BusyBox v1.30.1 (1:1.30.1-4ubuntu6.3) built-in shell (ash) Enter 'help' for a list of built-in commands. (initramfs) _

This frequently results from a corrupt filesystem, as detailed by this Ask Ubuntu ticket. The solution is to enter the command exit into the shell to report the corrupt filesystem. You may then repair it using fsck <device-file> as shown below.

BusyBox v1.30.1 (1:1.30.1-4ubuntu6.3) built-in shell (ash) Enter 'help' for a list of built-in commands. (initramfs) exit The root filesystem on /dev/mapper/vgkubuntu-root requires a manual fsck BusyBox v1.30.1 (1:1.30.1-4ubuntu6.3) built-in shell (ash) Enter 'help' for a list of built-in commands. (initramfs) fsck /dev/mapper/vgkubuntu-root -y fsck from util-linux 2.34 e2fsck 1.45.5 (07-Jan-2020) /dev/mapper/vgkubuntu-root contains a filesystem with errors, check forced.

After the filesystem repair is complete, type in reboot or exit to reboot the system. If the repair was good (which it usually is), the system should now boot normally.

Fix Your System Using FocusRx

Focus systems have a recovery tool called FocusRx which can identify and resolve many issues:

Check if the /boot partition is too full and fix it
Check and remove any xorg.conf file
Repair broken or incomplete packages
Update and reinstall key libraries
Analyze NVIDIA GFX, CUDA, and DL libraries and harmonize so they work
Fix many third-party repositories and remove duplicates and conflicts
Update the initial RAM disk

You can run FocusRx as shown below.

Connect to an Ethernet cable and AC power.
Reboot the system. If the default kernel does not boot, use the kernel selection screen, Advanced Options to select a different kernel if available.
If you can boot to a GUI, sign in and run Start Menu > Kubuntu Focus Tools > FocusRx System Repair.
If you cannot boot to a GUI, and instead see a black screen and cursor, press [CTRL][ALT][F2] to get a virtual terminal. Sign in as your user and then enter focusrx -f.
In FocusRx, elect to run package-check when prompted
If the tool shows your system disk is 100% full, remove unneeded files to free at least 10 GB before proceeding.
Follow the prompts and reboot when finished.

Reset a User Password

If you forget your user password, you can reset it using Recovery Mode if the following conditions are met:

The root account's password is NOT set
You have physical access to the system
The disk is unencrypted, or you know the decryption passphrase.

1. If the system is already powered on, shut it down.

2a. Boot the system. If the root filesystem is BTRFS, which is the default in 24.04, you should see a GRUB menu appear shortly after pressing the power button.

2b. If the root filesystem is NOT BTRFS, you will need to make it appear: immediately after the boot logo (like the Kubuntu Focus logo) appears, press right-shift (all models except XE) or escape (XE models). If the boot proceeds to a disk decryption or user login screen, it has gone too far and you will need to reboot to try again. If you press and hold the power button to shut down during boot, this will likely cause the GRUB menu to appear on the next boot. Once you see the GRUB menu, proceed to the next step.

To reset a user password, select Advanced Options for Kubuntu at the GRUB menu.

3. When the GRUB menu appears, promptly press the down arrow key to highlight "Advanced Options for Kubuntu" and press Enter.

4. In the next screen, press the down arrow key to highlight the first "(recovery mode)" option shown, then press Enter.

Choose the first recovery mode option on the list.

5. If your disk is encrypted, type your passphrase when prompted and press Enter. You cannot access the system if you do not have the disk passphrase.

6. You will see a grey box on a colored background with a list of options. Press the down arrow key to highlight the "root" option and press Enter. Directly below the grey box, you will be prompted to "Press Enter for maintenance". Press Enter.

Select 'root' from the list of options, then press Enter twice to gain access to the system.

7. You should now be able to type below the grey box as root. Type sudo mount -o remount,rw / and then press Enter to enable the ability to change the system.

8. Next, type ls /home and press Enter to list the users in the /home directory. Find your username and remember it; it will be required below.

9. Next, type passwd username, replacing username with your username from above, and press Enter. You will be prompted to enter your new password twice. Enter the same password each time.

10. Type reboot and press Enter to perform a normal reboot. After this, you should be able to use your new password to log in.

Enable the ability to change the system, determine your username, then use 'passwd' to reset your password. Reboot when done.

Again, this procedure only works if the root password is NOT set. In the event you DO have the root password set, things get messier. This method can provide some guidance.

Use a Live USB for Recovery

Please Download the ISO Disk Image and create a bootable USB flash drive. Then return here to proceed.

Boot using the USB flash drive as shown below.

Power-off the computer. Insert the USB flash drive into a USB type A port, and remove any other flash drives.
Power-on the computer and immediately and repeatedly tap [F7] to see the BIOS list of bootable disks. If this doesn't work, you might tap [F2] or [ESC] and select the boot drive in the BIOS. In either case, boot from the USB flash drive. The name of this drive will depend on the brand of drive you use.
Within 5 seconds after booting, you should be presented with a black-and-white boot menu. Allow the system to proceed with the default Start Kubuntu option.
After about a minute, the system should present you with a graphical menu with [ Try Kubuntu ] and [ Install Kubuntu ] options. If this does not occur after 2 minutes, try again with the Start Kubuntu (safe graphics) option.
Click [ Try Kubuntu ].
The Live Boot environment will start with a full Kubuntu desktop

24.04 LTS (Noble): Use chroot to Recover a System

1. Use the live USB procedure (above) to boot into the Try Kubuntu mode. Then open a Konsole terminal and enter the lines as shown below.

2a. ENCRYPTED DRIVE ONLY: Decrypt the drive and mount the root filesystem.

sudo -i # Find drive ID and decrypt mount /dev/nvme0n1p2 /mnt [ -d '/mnt/@boot' ] && GRUB_CFG='/mnt/@boot/grub/grub.cfg' \ || GRUB_CFG='/mnt/grub/grub.cfg' DRIVE_ID="$( sed -n '/luks/s/.*$luks-\([a-z0-9]*-*$*\).*/\1/p;/luks/q' \ "$GRUB_CFG" )" umount /mnt cryptsetup luksOpen /dev/nvme0n1p3 "$DRIVE_ID" # Mount decrypted drive mount "/dev/mapper/$DRIVE_ID" -o subvol=@ /mnt 2>/dev/null \ || mount "/dev/mapper/$DRIVE_ID" /mnt mount "/dev/mapper/$DRIVE_ID" -o subvol=@home /mnt/home 2>/dev/null # Proceed if you see 'etc' and 'home': cd /mnt ls

2b. UNENCRYPTED DRIVE ONLY: Mount the root filesystem.

sudo -i # Mount drive mount /dev/nvme0n1p3 -o subvol=@ /mnt 2>/dev/null \ || mount /dev/nvme0n1p3 /mnt # Proceed if you see 'etc' and 'home': cd /mnt ls

3. Back up your data.

If you haven't yet backed up your data, please do so NOW! See Backup for Clean Install to save your important files to a separate drive. You can find your user data under /mnt/home/. While each subsequent step below is usually safe, each brings additional risk because of an unknown system state or human error. Better safe than sorry.

4. Mount the boot and boot/efi filesystems.

# Mount boot and boot/efi cd /mnt mount /dev/nvme0n1p2 -o subvol=@boot boot 2>/dev/null \ || mount /dev/nvme0n1p2 boot mount /dev/nvme0n1p1 boot/efi # Proceed if you see 'vmlinuz' and 'initrd.img': ls boot # Proceed if you see 'EFI': ls boot/efi

5. Set up BTRFS mounts

# Look for BTRFS mount directories ls /mnt # If 'btrfs_main' and 'btrfs_boot' are not present, skip to step 6, # otherwise continue mount /dev/nvme0n1p2 -o subvolid=5 /mnt/btrfs_boot # FOR ENCRYPTED SYSTEMS: GRUB_CFG='/mnt/boot/grub/grub.cfg' DRIVE_ID="$( sed -n '/luks/s/.*$luks-\([a-z0-9]*-*$*\).*/\1/p;/luks/q' \ "$GRUB_CFG" )" mount "/dev/mapper/$DRIVE_ID" -o subvolid=5 /mnt/btrfs_main # FOR UNENCRYPTED SYSTEMS: mount /dev/nvme0n1p3 -o subvolid=5 /mnt/btrfs_main

6. Prepare and use chroot.

cd /mnt mount -t proc /proc proc mount --rbind /sys sys mount --rbind /dev dev rm etc/resolv.conf cp /etc/resolv.conf etc/resolv.conf chroot .

7. Once the system has successfully switched to chroot mode, you may run FocusRx (above) to fix packages and other common issues.

focusrx -f # One may also repair /etc/default/grub # and run update-grub

8. Here are a few more steps you might try if FocusRx does not solve the problem:

Attempt to fix broken packages using apt by typing sudo apt update && sudo apt full-upgrade (FocusRx also does this).
If GUI tools like Discover are not available, use apt or aptitude to inspect, install, or uninstall packages that may have caused the problem. You can navigate the aptitude interface in the terminal using the keyboard.

See this article for additional details on using chroot.

9. When you finish modifying the chroot environment, enter exit into the terminal. Close the terminal and restart. If the repairs worked, the system should start as normal.

22.04 LTS (Jammy): Use chroot to Recover a System

1. Use the live USB procedure (above) to boot into the Try Kubuntu mode. Then open a Konsole terminal and enter the lines as shown below.

2a. ENCRYPTED DRIVE ONLY: Decrypt the drive and mount the root filesystem.

sudo -i # Decrypt drive cryptsetup luksOpen /dev/nvme0n1p3 nvme0n1p3_crypt # Mount decrypted drive mount /dev/mapper/vgkubuntu-root /mnt # Proceed if you see 'etc' and 'home': cd /mnt ls

2b. UNENCRYPTED DRIVE ONLY: Mount the root filesystem.

sudo -i # Mount drive mount /dev/nvme0n1p2 /mnt # Proceed if you see 'etc' and 'home': cd /mnt ls

3. Back up your data.

4a. ENCRYPTED DRIVE ONLY: Mount the boot and boot/efi filesystems.

# Mount boot and boot/efi cd /mnt mount /dev/nvme0n1p2 boot mount /dev/nvme0n1p1 boot/efi # Proceed if you see 'vmlinuz' and 'initrd.img': ls boot # Proceed if you see 'EFI': ls boot/efi

4b. UNENCRYPTED DRIVE ONLY: Mount the boot/efi filesystem.

# Mount boot/efi cd /mnt mount /dev/nvme0n1p1 boot/efi # Proceed if you see 'EFI': ls boot/efi

5. Prepare and use chroot.

cd /mnt mount -t proc /proc proc mount --rbind /sys sys mount --rbind /dev dev rm etc/resolv.conf cp /etc/resolv.conf etc/resolv.conf chroot .

6. Once the system has successfully switched to chroot mode, you may run FocusRx (above) to fix packages and other common issues.

focusrx -f # One may also repair /etc/default/grub # and run update-grub

7. Here are a few more steps you might try if FocusRx does not solve the problem:

Attempt to fix broken packages using apt by typing sudo apt update && sudo apt full-upgrade (FocusRx also does this).
If GUI tools like Discover are not available, use apt or aptitude to inspect, install, or uninstall packages that may have caused the problem. You can navigate the aptitude interface in the terminal using the keyboard.

See this article for additional details on using chroot.

8. When you finish modifying the chroot environment, enter exit into the terminal. Close the terminal and restart. If the repairs worked, the system should start as normal.

Revisions

This is a partial revision history. See the git repository for all entries.

2025-06-04 fbfac979 Clarify Kubuntu 24.04 LTS with KFS
2025-04-19 274c0ff1 Update grammar and content per audit
2025-03-03 02a8831f Update System Rollback images
2025-02-27 a3381712 Normalize app names, descriptions, keywords, fix typos and minor issues
2024-12-06 35123b93 Normalize Hints Widget name and keyboard shortcut format
2024-11-13 e6b6729d Improve usb flash drive boot instructions
2024-09-10 9ae3566f Add bookmark links
2024-08-19 57a2389d Add white theme
2024-08-08 dc4e717b Add detailed password reset instructions
2024-07-28 ee7b4601 Update metadata content, collapsable sections, lightbox
2024-07-26 7814a97d Sync primary images between guided solutions slideshow and articles
2024-07-24 f6fedad2 Add lightboxes
2024-07-17 75b94dae Link checker audit and fixes
2024-07-16 e9155e41 Merge master link fixes
2024-07-16 1a734154 Update for Noble ISO release
2024-06-09 49dc0ff9 Enhance instructions
2024-06-08 ae03fd46 Update for Noble
2024-06-07 fd17f884 Move rollback images to their proper location
2024-06-07 333ba330 Update aptitude image and references
2024-06-05 461bd00f Update for Noble
2024-03-18 fb9b592d Add syntax highlighting for codeblocks
2023-11-18 e770b1c6 Add search and help bar
2023-01-25 5a05a952 Content fixes
2022-10-20 9fa483fa Clarify chroot section
2022-07-06 7c6e13f5 Update for 22.04 images
2022-01-22 97da7ffe Reference USB snapshot in backup article
2021-10-10 5728326e Reformat to 2-column
2021-09-22 dc862884 Update link and headline colors
2021-08-23 681261b4 Review and update codeblocks
2021-08-22 c1974de6 Add USB Drive Snapshot
2021-08-22 c1974de6 Add CHROOT Recovery Steps
2021-08-19 20a66a1c Add Busybox Shell Recovery
2021-08-05 c25e459e Fix Grammar Mistakes
2021-07-23 9e6157ce Add FocusRx Direction
2021-05-17 c75588e9 First publication

Disclaimer

We try hard to provide a useful solution validated by professionals. However, we cannot anticipate every situation, and therefore cannot guarantee this procedure will work for your needs. Always backup your data and test the solution to determine the correct procedure for you.

THIS SOLUTION IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOLUTION, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.