diff --git a/machines/migrations/0096_auto_20181013_1417.py b/machines/migrations/0096_auto_20181013_1417.py
new file mode 100644
index 00000000..745fb523
--- /dev/null
+++ b/machines/migrations/0096_auto_20181013_1417.py
@@ -0,0 +1,22 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.7 on 2018-10-13 12:17
+from __future__ import unicode_literals
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('machines', '0095_auto_20180919_2225'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='machine',
+            name='user',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL),
+        ),
+    ]
diff --git a/machines/models.py b/machines/models.py
index 282fc1ab..4caca48a 100644
--- a/machines/models.py
+++ b/machines/models.py
@@ -55,7 +55,7 @@ from re2o.mixins import AclMixin, RevMixin
 class Machine(RevMixin, FieldPermissionModelMixin, models.Model):
     """ Class définissant une machine, object parent user, objets fils
     interfaces"""
-    user = models.ForeignKey('users.User', on_delete=models.PROTECT)
+    user = models.ForeignKey('users.User', on_delete=models.CASCADE)
     name = models.CharField(
         max_length=255,
         help_text=_("Optional"),
diff --git a/users/management/commands/clean_notyetactive.py b/users/management/commands/clean_notyetactive.py
index 40f80c03..44c5b24e 100644
--- a/users/management/commands/clean_notyetactive.py
+++ b/users/management/commands/clean_notyetactive.py
@@ -19,6 +19,7 @@
 from django.core.management.base import BaseCommand, CommandError
 
 from users.models import User
+from cotisations.models import Facture
 from preferences.models import OptionalUser
 from datetime import timedelta
 
@@ -28,7 +29,9 @@ class Command(BaseCommand):
     help = "Delete non members users (not yet active)"
 
     def handle(self, *args, **options):
+        """First deleting invalid invoices, and then deleting the users"""
         days = OptionalUser.get_cached_value('delete_notyetactive')
-        users = User.objects.filter(state=User.STATE_NOT_YET_ACTIVE).filter(registered__lte=timezone.now() - timedelta(days=days))
-        print("Deleting " + str(users.count()) + " users")
-        users.delete()
+        users_to_delete = User.objects.filter(state=User.STATE_NOT_YET_ACTIVE).filter(registered__lte=timezone.now() - timedelta(days=days)).exclude(facture__valid=True).distinct()
+        print("Deleting " + str(users_to_delete.count()) + " users")
+        Facture.objects.filter(user__in=users_to_delete).delete()
+        users_to_delete.delete()