diff --git a/chrono/apps/snapshot/migrations/0002_snapshot_models.py b/chrono/apps/snapshot/migrations/0002_snapshot_models.py
index c838f567..b088246d 100644
--- a/chrono/apps/snapshot/migrations/0002_snapshot_models.py
+++ b/chrono/apps/snapshot/migrations/0002_snapshot_models.py
@@ -38,7 +38,7 @@ class Migration(migrations.Migration):
                 (
                     'user',
                     models.ForeignKey(
-                        null=True, on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL
+                        null=True, on_delete=django.db.models.deletion.SET_NULL, to=settings.AUTH_USER_MODEL
                     ),
                 ),
             ],
@@ -72,7 +72,7 @@ class Migration(migrations.Migration):
                 (
                     'user',
                     models.ForeignKey(
-                        null=True, on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL
+                        null=True, on_delete=django.db.models.deletion.SET_NULL, to=settings.AUTH_USER_MODEL
                     ),
                 ),
             ],
@@ -106,7 +106,7 @@ class Migration(migrations.Migration):
                 (
                     'user',
                     models.ForeignKey(
-                        null=True, on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL
+                        null=True, on_delete=django.db.models.deletion.SET_NULL, to=settings.AUTH_USER_MODEL
                     ),
                 ),
             ],
@@ -140,7 +140,7 @@ class Migration(migrations.Migration):
                 (
                     'user',
                     models.ForeignKey(
-                        null=True, on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL
+                        null=True, on_delete=django.db.models.deletion.SET_NULL, to=settings.AUTH_USER_MODEL
                     ),
                 ),
             ],
@@ -174,7 +174,7 @@ class Migration(migrations.Migration):
                 (
                     'user',
                     models.ForeignKey(
-                        null=True, on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL
+                        null=True, on_delete=django.db.models.deletion.SET_NULL, to=settings.AUTH_USER_MODEL
                     ),
                 ),
             ],
diff --git a/chrono/apps/snapshot/models.py b/chrono/apps/snapshot/models.py
index 6f78b811..af94ffd6 100644
--- a/chrono/apps/snapshot/models.py
+++ b/chrono/apps/snapshot/models.py
@@ -45,7 +45,7 @@ class WithSnapshotMixin:
 
 class AbstractSnapshot(models.Model):
     timestamp = models.DateTimeField(auto_now_add=True)
-    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, null=True)
+    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.SET_NULL, null=True)
     comment = models.TextField(blank=True, null=True)
     serialization = models.JSONField(blank=True, default=dict)
     label = models.CharField(_('Label'), max_length=150, blank=True)
diff --git a/tests/manager/test_snapshot.py b/tests/manager/test_snapshot.py
index 2d96ad69..b56c48ea 100644
--- a/tests/manager/test_snapshot.py
+++ b/tests/manager/test_snapshot.py
@@ -95,6 +95,11 @@ def test_agenda_history(settings, app, admin_user):
     assert 'Snapshot (%s) -  (Version 41.0)' % snapshot1.pk in resp
     assert 'Snapshot (%s) -  (Version 42.0)' % snapshot2.pk in resp
 
+    assert AgendaSnapshot.objects.update(user=admin_user)
+    admin_user.delete()
+    assert AgendaSnapshot.objects.count() == 2
+    assert AgendaSnapshot.objects.filter(user__isnull=True).count() == 2
+
 
 def test_agenda_history_as_manager(app, manager_user):
     agenda = Agenda.objects.create(slug='foo', label='Foo')
@@ -195,6 +200,11 @@ def test_category_history(settings, app, admin_user):
     assert 'Snapshot (%s) -  (Version 41.0)' % snapshot1.pk in resp
     assert 'Snapshot (%s) -  (Version 42.0)' % snapshot2.pk in resp
 
+    assert CategorySnapshot.objects.update(user=admin_user)
+    admin_user.delete()
+    assert CategorySnapshot.objects.count() == 2
+    assert CategorySnapshot.objects.filter(user__isnull=True).count() == 2
+
 
 def test_events_type_history(settings, app, admin_user):
     events_type = EventsType.objects.create(slug='foo', label='Foo')
@@ -273,6 +283,11 @@ def test_events_type_history(settings, app, admin_user):
     assert 'Snapshot (%s) -  (Version 41.0)' % snapshot1.pk in resp
     assert 'Snapshot (%s) -  (Version 42.0)' % snapshot2.pk in resp
 
+    assert EventsTypeSnapshot.objects.update(user=admin_user)
+    admin_user.delete()
+    assert EventsTypeSnapshot.objects.count() == 2
+    assert EventsTypeSnapshot.objects.filter(user__isnull=True).count() == 2
+
 
 def test_resource_history(settings, app, admin_user):
     resource = Resource.objects.create(slug='foo', label='Foo')
@@ -347,6 +362,11 @@ def test_resource_history(settings, app, admin_user):
     assert 'Snapshot (%s) -  (Version 41.0)' % snapshot1.pk in resp
     assert 'Snapshot (%s) -  (Version 42.0)' % snapshot2.pk in resp
 
+    assert ResourceSnapshot.objects.update(user=admin_user)
+    admin_user.delete()
+    assert ResourceSnapshot.objects.count() == 2
+    assert ResourceSnapshot.objects.filter(user__isnull=True).count() == 2
+
 
 def test_unavailability_calendar_history(settings, app, admin_user):
     unavailability_calendar = UnavailabilityCalendar.objects.create(slug='foo', label='Foo')
@@ -425,6 +445,11 @@ def test_unavailability_calendar_history(settings, app, admin_user):
     assert 'Snapshot (%s) -  (Version 41.0)' % snapshot1.pk in resp
     assert 'Snapshot (%s) -  (Version 42.0)' % snapshot2.pk in resp
 
+    assert UnavailabilityCalendarSnapshot.objects.update(user=admin_user)
+    admin_user.delete()
+    assert UnavailabilityCalendarSnapshot.objects.count() == 2
+    assert UnavailabilityCalendarSnapshot.objects.filter(user__isnull=True).count() == 2
+
 
 def test_unavailability_calendar_history_as_manager(app, manager_user):
     unavailability_calendar = UnavailabilityCalendar.objects.create(slug='foo', label='Foo')