Troubleshooting

Fixing Broken Thumbnails on Ubuntu 24.04.4 LTS Caused by AppArmor User Namespaces

April 17, 2026

Linux, Desktop, Security, Troubleshooting

Ubuntu, Gnome, Apparmor, Security, Troubleshooting, Kernel, Desktop, Namespaces

Fixing Broken Thumbnails on Ubuntu 24.04.4 LTS Caused by AppArmor User Namespaces #

On my Ubuntu 24.04.4 LTS desktop, which I’d been using for about six months, I ran into a surprisingly stubborn issue: GNOME Files (Nautilus) completely stopped generating thumbnails for both images and videos. At first glance it looked like a typical desktop breakage: thumbnail cache issues, missing codecs, or a corrupted Nautilus config. But none of the usual fixes helped.