diff --git a/eventplanner_gcal/google_sync.py b/eventplanner_gcal/google_sync.py
index 7e20ea7..5763773 100644
--- a/eventplanner_gcal/google_sync.py
+++ b/eventplanner_gcal/google_sync.py
@@ -340,24 +340,40 @@ def sync_from_local_to_google(service=None):
 
     all_events = get_all_gcal_events(service)
 
+    # Map gcal_id -> django_id for every blechreiz-owned event at Google
+    gcal_id_to_django_id = {}
     events_at_google_django_id = set()
-    events_at_google_google_id = set()
 
     for gcal_ev in all_events:
         try:
             django_id = int(gcal_ev["extendedProperties"]["private"]["blechreizID"])
             events_at_google_django_id.add(django_id)
-            events_at_google_google_id.add(gcal_ev["id"])
+            gcal_id_to_django_id[gcal_ev["id"]] = django_id
         except (KeyError, ValueError) as e:
             logger.warning(f"Invalid GCal event structure: {e}")
 
     local_events_django_id = set(Event.objects.all().values_list("pk", flat=True))
-    local_events_google_id = set(
-        GCalMapping.objects.all().values_list("gcal_id", flat=True)
-    )
+
+    # Repair GCalMapping for events that exist at Google but have no local mapping
+    # (can happen when a previous batch failed mid-way)
+    for gcal_id, django_id in gcal_id_to_django_id.items():
+        if django_id in local_events_django_id and not GCalMapping.objects.filter(gcal_id=gcal_id).exists():
+            try:
+                event = Event.objects.get(pk=django_id)
+                GCalMapping.objects.get_or_create(event=event, defaults={"gcal_id": gcal_id})
+                logger.info(f"Repaired missing mapping: GCal {gcal_id} <-> Event {django_id}")
+            except Event.DoesNotExist:
+                pass
 
     events_to_create_django_id = local_events_django_id - events_at_google_django_id
-    events_to_delete_google_id = events_at_google_google_id - local_events_google_id
+
+    # Only delete Google events whose local Event no longer exists
+    # (never delete based on missing GCalMapping — that's just a local cache)
+    events_to_delete_google_id = {
+        gcal_id
+        for gcal_id, django_id in gcal_id_to_django_id.items()
+        if django_id not in local_events_django_id
+    }
 
     batch = service.new_batch_http_request()
     batch_is_empty = True