diff --git a/app.py b/app.py
index a9fe568..6bbd5f7 100644
--- a/app.py
+++ b/app.py
@@ -9613,7 +9613,16 @@ def export_time_attendance_excel(records, project_name_for_filename, date_range_
             if _di + 1 >= len(sorted_dk):
                 continue
 
+            # Guard: _dk or _ndk may have been deleted by a prior iteration
+            # when all its records were moved to the previous day's bucket.
+            # Without this check, iterating the stale sorted_dk snapshot raises KeyError.
+            if _dk not in daily_location_data:
+                continue
+
             _ndk = sorted_dk[_di + 1]
+            if _ndk not in daily_location_data:
+                continue
+
             # Must be consecutive calendar days
             _dn  = datetime.strptime(_dk,  '%Y-%m-%d').date()
             _dn1 = datetime.strptime(_ndk, '%Y-%m-%d').date()
diff --git a/working_hours_calculator.py b/working_hours_calculator.py
index b9b13a1..bf15372 100644
--- a/working_hours_calculator.py
+++ b/working_hours_calculator.py
@@ -490,6 +490,14 @@ class WorkingHoursCalculator:
             for work_type in ['regular', 'SP', 'PW', 'PT']:
                 all_dates = sorted(daily_records_by_type[work_type].keys())
                 for i, date_key in enumerate(all_dates):
+                    # Guard: date_key may have been deleted by a prior iteration when all
+                    # its records were moved to the previous day's bucket.
+                    # Without this check, iterating the stale all_dates snapshot raises KeyError,
+                    # which is silently caught by the outer try/except and returns an empty
+                    # daily_hours dict — causing the employee to show zero rows in the export.
+                    if date_key not in daily_records_by_type[work_type]:
+                        continue
+
                     day_records = daily_records_by_type[work_type][date_key]
 
                     # Count unpaired check-ins (late evening)
@@ -513,6 +521,10 @@ class WorkingHoursCalculator:
                         continue
 
                     next_date_key = all_dates[i + 1]
+                    # Guard: next_date_key may also have been deleted by a prior iteration
+                    if next_date_key not in daily_records_by_type[work_type]:
+                        continue
+
                     # Verify it is truly the next day
                     from datetime import date as date_type
                     day_n   = datetime.strptime(date_key,      '%Y-%m-%d').date()