diff --git a/rugnux_vs_xds.py b/rugnux_vs_xds.py
index 2bf203c5..39bf080a 100755
--- a/rugnux_vs_xds.py
+++ b/rugnux_vs_xds.py
@@ -185,7 +185,8 @@ def run_rugnux(master, workdir, name, xds, rugnux_bin, threads, timeout, reuse):
     if reuse and cif.exists():
         return cif, None, None   # no fresh timing when we skip the run
 
-    cmd = [rugnux_bin, "-o", name, "--scaling-output", "cif"]
+    # rugnux always writes both MTZ and CIF now (the old --scaling-output flag was removed).
+    cmd = [rugnux_bin, "-o", name]
     if xds.get("anomalous"):
         cmd.append("-A")
     if xds.get("dmin"):