diff --git a/gregor_django/gregor_anvil/tests/test_views.py b/gregor_django/gregor_anvil/tests/test_views.py
index 22f32c35..017146b7 100644
--- a/gregor_django/gregor_anvil/tests/test_views.py
+++ b/gregor_django/gregor_anvil/tests/test_views.py
@@ -333,6 +333,14 @@ def test_rc_member_table(self):
         self.assertIn(account, table.data)
         self.assertNotIn(other_account, table.data)
 
+    def test_member_table_group_not_set(self):
+        obj = self.model_factory.create()
+        acm_factories.AccountFactory.create(verified=True)
+        self.client.force_login(self.user)
+        response = self.client.get(self.get_url(obj.pk))
+        table = response.context_data["tables"][1]
+        self.assertEqual(len(table.rows), 0)
+
     def test_rc_uploader_table(self):
         uploader_group = acm_factories.ManagedGroupFactory.create()
         obj = self.model_factory.create(uploader_group=uploader_group)
@@ -346,6 +354,14 @@ def test_rc_uploader_table(self):
         self.assertIn(account, table.data)
         self.assertNotIn(other_account, table.data)
 
+    def test_upload_table_group_not_set(self):
+        obj = self.model_factory.create()
+        acm_factories.AccountFactory.create(verified=True)
+        self.client.force_login(self.user)
+        response = self.client.get(self.get_url(obj.pk))
+        table = response.context_data["tables"][2]
+        self.assertEqual(len(table.rows), 0)
+
 
 class ResearchCenterListTest(TestCase):
     """Tests for the ResearchCenterList view."""
@@ -512,6 +528,14 @@ def test_member_table(self):
         self.assertIn(account, table.data)
         self.assertNotIn(other_account, table.data)
 
+    def test_member_table_group_not_set(self):
+        obj = self.model_factory.create()
+        acm_factories.AccountFactory.create(verified=True)
+        self.client.force_login(self.user)
+        response = self.client.get(self.get_url(obj.pk))
+        table = response.context_data["tables"][1]
+        self.assertEqual(len(table.rows), 0)
+
     def test_uploader_table(self):
         uploader_group = acm_factories.ManagedGroupFactory.create()
         obj = self.model_factory.create(uploader_group=uploader_group)
@@ -525,6 +549,14 @@ def test_uploader_table(self):
         self.assertIn(account, table.data)
         self.assertNotIn(other_account, table.data)
 
+    def test_upload_table_group_not_set(self):
+        obj = self.model_factory.create()
+        acm_factories.AccountFactory.create(verified=True)
+        self.client.force_login(self.user)
+        response = self.client.get(self.get_url(obj.pk))
+        table = response.context_data["tables"][2]
+        self.assertEqual(len(table.rows), 0)
+
 
 class PartnerGroupListTest(TestCase):
     """Tests for the ResearchCenterList view."""
diff --git a/gregor_django/gregor_anvil/views.py b/gregor_django/gregor_anvil/views.py
index b422a4b7..d925ad94 100644
--- a/gregor_django/gregor_anvil/views.py
+++ b/gregor_django/gregor_anvil/views.py
@@ -35,12 +35,18 @@ class ResearchCenterDetail(AnVILConsortiumManagerStaffViewRequired, MultiTableMi
     model = models.ResearchCenter
 
     def get_tables(self):
-        members = Account.objects.filter(
-            groupaccountmembership__group=self.object.member_group,
-        )
-        uploaders = Account.objects.filter(
-            groupaccountmembership__group=self.object.uploader_group,
-        )
+        if self.object.member_group is None:
+            members = Account.objects.none()
+        else:
+            members = Account.objects.filter(
+                groupaccountmembership__group=self.object.member_group,
+            )
+        if self.object.uploader_group is None:
+            uploaders = Account.objects.none()
+        else:
+            uploaders = Account.objects.filter(
+                groupaccountmembership__group=self.object.uploader_group,
+            )
         return [
             UserTable(User.objects.filter(research_centers=self.object)),
             tables.AccountTable(members, exclude=("user__research_centers", "number_groups")),
@@ -61,12 +67,18 @@ class PartnerGroupDetail(AnVILConsortiumManagerStaffViewRequired, MultiTableMixi
     model = models.PartnerGroup
 
     def get_tables(self):
-        members = Account.objects.filter(
-            groupaccountmembership__group=self.object.member_group,
-        )
-        uploaders = Account.objects.filter(
-            groupaccountmembership__group=self.object.uploader_group,
-        )
+        if self.object.member_group is None:
+            members = Account.objects.none()
+        else:
+            members = Account.objects.filter(
+                groupaccountmembership__group=self.object.member_group,
+            )
+        if self.object.uploader_group is None:
+            uploaders = Account.objects.none()
+        else:
+            uploaders = Account.objects.filter(
+                groupaccountmembership__group=self.object.uploader_group,
+            )
         return [
             UserTable(User.objects.filter(partner_groups=self.object)),
             tables.AccountTable(members, exclude=("user__research_centers", "number_groups")),