diff --git a/sensospot_data/dynamic_range.py b/sensospot_data/dynamic_range.py
index 9a6119a..20adbb6 100644
--- a/sensospot_data/dynamic_range.py
+++ b/sensospot_data/dynamic_range.py
@@ -53,6 +53,12 @@ def _reduce_overflow(data_frame):
     for next_time in rest_times:
         mask = result_frame[CALC_SPOT_OVERFLOW] == True  # noqa: E712
         next_frame = split_frames[next_time].set_index(PROBE_MULTI_INDEX)
+        rf_index = set(result_frame.index)
+        nf_index = set(next_frame.index)
+        diff = rf_index - nf_index | nf_index - rf_index
+        if diff:
+            num = len(diff)
+            raise ValueError(f"XDR: Scan Data is incomplete, differs on {num} probes")
         result_frame.loc[mask] = next_frame.loc[mask]
 
     return result_frame.reset_index()