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Synology Troubleshooting

ErrNo 13: Access Denied in Portainer or Container Manager

This is the usual Synology permission issue, and you can fix it over SSH:

  1. Enable SSH on the NAS if you haven't (see the DSM guide).
  2. SSH in with your DSM admin account (same credentials as the DSM web UI).
  3. Find your UID/GID by typing id and noting uid=NNNN(user) gid=NNNN(group).
  4. Fix permissions on every host path:
sudo chown -R <user>:<group> /path/to/library
sudo chmod -R a=,a+rX,u+w,g+w /path/to/library

sudo chown -R <user>:<group> /path/to/assets
sudo chmod -R a=,a+rX,u+w,g+w /path/to/assets

sudo chown -R <user>:<group> /path/to/config
sudo chmod -R a=,a+rX,u+w,g+w /path/to/config

The paths are whatever you mounted into the container as /romm/library, /romm/assets, and /romm/config.

  1. Restart the containers with docker compose restart or click Restart in Container Manager.

Scans should now complete cleanly.

Tip

If you're still getting permission errors inside the container after this, the UID/GID running inside the container doesn't match the host files. Either change the container's user: directive to match your Synology user, or change the host file ownership to match the container's expected UID.

The permission-mode string comes from DrFrankenstein's Docker user guide.

DSM's built-in MariaDB conflicts

Synology ships its own MariaDB on port 3306. If you try to run RomM's MariaDB container on the same port, one of them won't bind. To fix, map MariaDB to a different host port in your compose file (the Synology install guide uses 3309:3306).

"Page not found" on first open

The first run takes a few minutes on a NAS while the DB initialisation, migrations, and static asset seeding complete. Wait until the logs show the server is ready, then refresh the page:

sudo docker compose logs -f

Volume drift after DSM updates

DSM occasionally rotates Docker's data directory or the BTRFS subvolume paths after an update. The container starts but it looks like all your data is gone. To fix:

  1. Don't panic. Your host-mounted paths (/volume1/...) aren't touched.
  2. Check your compose file. Any volumes declared as named Docker volumes (as opposed to host bind mounts) might have been recreated empty.
  3. Prefer host bind mounts on Synology specifically (/volume1/docker/romm/resources) instead of a named romm_resources volume. The Synology install guide uses this pattern.