diff --git a/docker-compose.yml b/docker-compose.yml
index edbffc2..f57ad03 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -18,7 +18,7 @@ services:
       # cannot cross Docker bind mounts, even on the same disk.
       #   host  (Albums)  -> /data/Music/Albums
       #   slave (Singles) -> /data/Music/Instances/cdnutter/Singles
-      - /mnt/user/Sapphire:/data
+      - /mnt/user/Sapphire:/data:ro
     restart: unless-stopped
     networks:
       - chromanet