diff --git a/src/dials/algorithms/merging/merge.py b/src/dials/algorithms/merging/merge.py
index 661b906818..15f055b304 100644
--- a/src/dials/algorithms/merging/merge.py
+++ b/src/dials/algorithms/merging/merge.py
@@ -312,6 +312,7 @@ def merge_scaled_array(
         stats_data.anom_merging_statistics_result = anom_stats
         # try to fit resolution
         resolution_cut_criterion = ""
+        d_min = None
         try:
             if applied_d_min is None:
                 if not resolution_fit_options: