Prove the running Plex instance and its mounted state path before editing any configuration file.
Multiple installs, containers, backups, and old app-data directories can leave several files with plausible names. Stop guessing from filenames. Identify the active process or container, inspect its configuration mount, and compare the file timestamp or a harmless setting change with the instance that is actually running.
Identify the Runtime Before the File
A native service and a container can use different filesystem views even on the same host. The first step is to identify which process or container owns port 32400 and the Plex data directory.
In a containerized media stack, explicit configuration volumes determine which host directory the running Plex instance actually sees, so trace the mount before assuming a host-side file is active.
Inspect the running container or service definition and write down the host path and the path Plex sees. If there is no clear mapping, resolve that ambiguity before editing anything.
Confirm the Preferences File Belongs to That State Tree
Preferences.xml carries server identity and account-related settings, but an old copy in a backup or previous install can look valid. Context matters more than the filename alone.
Preferences.xml state is tied to the mounted Plex configuration path, so the active mount is more authoritative than a matching filename found elsewhere.
Compare modification time and ownership with the running state directory, then make one reversible setting change through the Plex UI. Confirm only the expected file changes.
Watch for Duplicate State Mounts
Container migrations can accidentally mount one path for startup and another for backup or manual editing. That creates the illusion that settings are ignored.
Keep the persistent state mapping in one place in your deployment definition. The persistent app-data mapping should point to one canonical Plex state directory rather than several partially copied trees.
Restart Plex after a controlled setting change and confirm the value persists. If it reverts, inspect the mount and ownership before changing the XML directly.
Back Up the Active State Before Manual Edits
Manual file editing should be a last resort because identity, account, and database state are tightly coupled to the running server. Preserve the active file before changing it.
Before editing server identity or preferences, preserve the active state tree; Plex backup and migration depends on carrying the real server data and paths forward, not a stray configuration copy.
Stop Plex when the edit requires a stable file, copy the active configuration, make the smallest change, then restart and verify one expected result. Roll back immediately if unrelated settings change.
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