Public bug reported:
Summary
On a fresh installation of Ubuntu 24.04.4, installed on 17 July 2026,
Nautilus thumbnail generation works correctly before applying system
updates.
After updating the system on the same day, the apparmor package is
upgraded from:
4.0.1really4.0.1-0ubuntu0.24.04.5 to:
4.0.1really4.0.1-0ubuntu0.24.04.7
I did not install version 4.0.1really4.0.1-0ubuntu0.24.04.6; the upgrade
was directly from .5 to .7.
During package configuration, the following message appears:
Removing obsolete conffile /etc/apparmor.d/nautilus ...
After this operation, the file:
/etc/apparmor.d/nautilus
is removed.
As a consequence, Nautilus stops generating thumbnails for all file
types.
Restoring the missing AppArmor profile restores normal thumbnail
generation.
Steps to reproduce
1. Install Ubuntu 24.04.4.
2. Before running updates, verify that Nautilus correctly generates thumbnails.
3. Check that AppArmor version is: apparmor 4.0.1really4.0.1-0ubuntu0.24.04.5
4. Verify that the file exists: ls -l /etc/apparmor.d/nautilus
5. Update the system.
The system upgrades AppArmor directly to: apparmor
4.0.1really4.0.1-0ubuntu0.24.04.7
6. During package configuration, the following message appears:
Removing obsolete conffile /etc/apparmor.d/nautilus ...
7. After the upgrade the file is missing.
8. Open folders containing images or other files in Nautilus.
Nautilus stops generating thumbnails.
The directory: ~/.cache/thumbnails/fail is populated with failed thumbnail
entries.
Additional investigation
The package still declares the file as a conffile:
Command:
dpkg-query -W -f='${Conffiles}\n' apparmor | grep nautilus
Output:
/etc/apparmor.d/nautilus 57287a789351c7416b3d96538253ced2
Therefore the file is expected by the package, but it is removed during upgrade.
Workaround
The missing conffile can be restored with:
sudo apt-get -o Dpkg::Options::="--force-confmiss" install --reinstall apparmor
After restoring: /etc/apparmor.d/nautilus Nautilus thumbnail generation works
again.
Possible cause
The upgrade process incorrectly treats `/etc/apparmor.d/nautilus` as an
obsolete conffile and removes it.
ProblemType: Bug
DistroRelease: Ubuntu 24.04
Package: apparmor 4.0.1really4.0.1-0ubuntu0.24.04.7
ProcVersionSignature: Ubuntu 7.0.0-28.28~24.04.1-generic 7.0.12
Uname: Linux 7.0.0-28-generic x86_64
ApportVersion: 2.28.2-0ubuntu0.1
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Fri Jul 17 19:14:10 2026
InstallationDate: Installed on 2026-07-17 (0 days ago)
InstallationMedia: Ubuntu 24.04.4 LTS "Noble Numbat" - Release amd64 (20260210)
ProcEnviron:
LANG=it_IT.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=xterm-256color
XDG_RUNTIME_DIR=<set>
ProcKernelCmdline: BOOT_IMAGE=/boot/vmlinuz-7.0.0-28-generic
root=UUID=672956b1-8ab5-4db8-9fd6-aa09eec8d0d9 ro quiet splash vt.handoff=7
SourcePackage: apparmor
UpgradeStatus: No upgrade log present (probably fresh install)
** Affects: apparmor (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug noble wayland-session
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https://bugs.launchpad.net/bugs/2161120
Title:
Ubuntu 24.04.4 apparmor upgrade removes /etc/apparmor.d/nautilus
conffile causing Nautilus thumbnail generation failure
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