diff --git a/Containers/nextcloud/entrypoint.sh b/Containers/nextcloud/entrypoint.sh
index b90b4011..04f7bbde 100644
--- a/Containers/nextcloud/entrypoint.sh
+++ b/Containers/nextcloud/entrypoint.sh
@@ -908,6 +908,12 @@ if [ "$EUROOFFICE_ENABLED" = 'yes' ]; then
         fi
 
         php /var/www/html/occ config:app:set eurooffice DocumentServerUrl --value="https://$EUROOFFICE_HOST"
+
+        # Register EuroOffice preview provider in the explicit allowlist.
+        # Use a high fixed index (50) to avoid colliding with AIO's seeded indices (1-7, 23).
+        if ! php /var/www/html/occ config:system:get enabledPreviewProviders | grep -q "Eurooffice"; then
+            php /var/www/html/occ config:system:set enabledPreviewProviders 50 --value="OCA\Eurooffice\Preview"
+        fi
     fi
 else
     # Remove EuroOffice app if disabled and removal is requested