diff --git a/lib/adf_diag.py b/lib/adf_diag.py
index bf15e4840..314aa679a 100644
--- a/lib/adf_diag.py
+++ b/lib/adf_diag.py
@@ -1199,7 +1199,7 @@ def move_tsfiles_for_mdtf(self, verbose):
                     else:
                         if verbose > 0:
                             print(
-                                "ERROR: None of the frequency options {freq_string_options} are present in the time_period_freq attribute {time_perido_freq}"
+                                f"WARNING: None of the frequency options {freq_string_options} are present in the time_period_freq attribute {time_perido_freq}"
                             )
                             print("Skipping {adf_file}")
                             freq = "frequency_missing"