diff --git a/AKModel/models.py b/AKModel/models.py
index 5406a8e80a9caf4202bf29b194851fb77cf37c34..8831be92f918210de9c757d2a08d670da137c4f1 100644
--- a/AKModel/models.py
+++ b/AKModel/models.py
@@ -383,7 +383,7 @@ class Event(models.Model):
             )
 
     @transaction.atomic
-    def schedule_from_json(self, schedule: str) -> None:
+    def schedule_from_json(self, schedule: str) -> int:
         """Load AK schedule from a json string.
 
         :param schedule: A string that can be decoded to json, describing
@@ -401,6 +401,7 @@ class Event(models.Model):
             for timeslot in block
         }
 
+        slots_updated = 0
         for scheduled_slot in schedule["scheduled_aks"]:
             scheduled_slot["timeslot_ids"] = list(map(int, scheduled_slot["timeslot_ids"]))
             start_timeslot = timeslot_dict[min(scheduled_slot["timeslot_ids"])].avail
@@ -414,6 +415,8 @@ class Event(models.Model):
             assert solver_duration + 1e-4 >= slot.duration
 
             slot.save()
+            slots_updated += 1
+        return slots_updated
 
 class AKOwner(models.Model):
     """ An AKOwner describes the person organizing/holding an AK.
diff --git a/AKModel/views/ak.py b/AKModel/views/ak.py
index 90599a1ba26809c21c17495891ce4c527b827c26..f180f9582325e3d3188b25fed902a99c4dd4c87a 100644
--- a/AKModel/views/ak.py
+++ b/AKModel/views/ak.py
@@ -61,7 +61,7 @@ class AKJSONExportView(AdminViewMixin, FilterByEventSlugMixin, ListView):
 
     def _test_ak_fixed_in_slot(self, ak_id, slot: Availability, ak_fixed: dict) -> bool:
         """Test if AK defined by `ak_id` is fixed to happen during slot."""
-        if not ak_id in ak_fixed:
+        if ak_id not in ak_fixed:
             return False
 
         fixed_slot = Availability(self.event, start=ak_fixed[ak_id].start, end=ak_fixed[ak_id].end)
diff --git a/AKModel/views/manage.py b/AKModel/views/manage.py
index 1bad9534efd6fe81fa70ebf30fbdf84aad476967..3acb05fd29a6e91cd17f45e9ed43d889a67da22c 100644
--- a/AKModel/views/manage.py
+++ b/AKModel/views/manage.py
@@ -257,6 +257,18 @@ class AKScheduleJSONImportView(EventSlugMixin, IntermediateAdminView):
     title = _("AK Schedule JSON Import")
 
     def form_valid(self, form):
-        self.event.schedule_from_json(form.data["json_data"])
+        try:
+            number_of_slots_changed = self.event.schedule_from_json(form.data["json_data"])
+            messages.add_message(
+                self.request,
+                messages.SUCCESS,
+                _("Successfully imported {n} slot(s)").format(n=number_of_slots_changed)
+            )
+        except ValueError as ex:
+            messages.add_message(
+                self.request,
+                messages.ERROR,
+                _("Importing an AK schedule failed! Reason: ") + str(ex),
+            )
 
         return redirect("admin:event_status", self.event.slug)