Troubleshooting

A “degraded mode” banner#

monbooru can’t read the gallery folder. What’s already indexed stays browsable, but syncing and the watcher are off. Fix the path or its permissions and restart.

“Library too old to upgrade directly”#

monbooru may upgrades a gallery’s database from the last two minor releases. A gallery last opened by something older stops the start with this message, and names a release that still upgrades it: run that release once against the same folders, then start the current one again. Nothing is changed in the meantime.

Thumbnails are missing#

Run Settings -> Maintenance -> Rebuild thumbnails. Videos, animated GIFs, AVIF and JPEG XL need ffmpeg, which comes with the Docker image and the bundled downloads. If you installed your own, restart monbooru so it finds it (JPEG XL needs a build with libjxl).

The bundled ffmpeg is a small build that only covers the formats monbooru supports. If one of your videos uses a codec it refuses and you have a full ffmpeg installed, delete ffmpeg and ffprobe from the monbooru folder and it uses yours instead.

New files don’t show up#

Check that they’re inside the gallery folder, under the size limit in Settings -> General, and in a supported format, then press the sync button. A file the watcher missed is always picked up by a sync.

The watcher stops with “no space left on device”#

That’s Linux’s limit on watched folders (inotify_add_watch in the log). Raise fs.inotify.max_user_watches on the host, not inside the container, and restart. If the log says “too many open files” instead, raise fs.inotify.max_user_instances. Or turn the watcher off in Settings -> General and sync by hand.

Moving or deleting a file fails with a permission error#

monbooru takes ownership of new files as it indexes them so it can move or delete them later. A file that still belongs to another user has to be made writable for the user monbooru runs as. On Docker, taking ownership needs the CHOWN and DAC_OVERRIDE capabilities; see Docker details.

Locked out of the login#

After a few wrong passwords the login makes you wait before trying again. The wait is short and resets after a few quiet minutes, and restarting monbooru clears it.

The API answers 503 api_disabled#

No API token exists yet. Create one under Settings -> Authentication; see API and plugins.