diff --git a/hc/accounts/tests/test_login.py b/hc/accounts/tests/test_login.py
index 92da015c..df67eccd 100644
--- a/hc/accounts/tests/test_login.py
+++ b/hc/accounts/tests/test_login.py
@@ -4,6 +4,7 @@ from django.test import TestCase
 from hc.api.models import Check
 from django.conf import settings
 
+
 class LoginTestCase(TestCase):
 
     def test_it_sends_link(self):
@@ -24,7 +25,8 @@ class LoginTestCase(TestCase):
 
         # And email sent
         self.assertEqual(len(mail.outbox), 1)
-        self.assertEqual(mail.outbox[0].subject, 'Log in to {0}'.format(getattr(settings, "SITE_NAME")))
+        subject = "Log in to %s" % settings.SITE_NAME
+        self.assertEqual(mail.outbox[0].subject, subject)
 
         # And check should be associated with the new user
         check_again = Check.objects.get(code=check.code)
@@ -34,3 +36,24 @@ class LoginTestCase(TestCase):
         self.client.session["bad_link"] = True
         self.client.get("/accounts/login/")
         assert "bad_link" not in self.client.session
+
+    def test_it_handles_missing_welcome_check(self):
+
+        # This check does not exist in database,
+        # but login should still work.
+        session = self.client.session
+        session["welcome_code"] = "00000000-0000-0000-0000-000000000000"
+        session.save()
+
+        form = {"email": "alice@example.org"}
+
+        r = self.client.post("/accounts/login/", form)
+        assert r.status_code == 302
+
+        # An user should have been created
+        self.assertEqual(User.objects.count(), 1)
+
+        # And email sent
+        self.assertEqual(len(mail.outbox), 1)
+        subject = "Log in to %s" % settings.SITE_NAME
+        self.assertEqual(mail.outbox[0].subject, subject)
diff --git a/hc/accounts/views.py b/hc/accounts/views.py
index 8d67b218..cfcdef8e 100644
--- a/hc/accounts/views.py
+++ b/hc/accounts/views.py
@@ -39,17 +39,24 @@ def _make_user(email):
 
 
 def _associate_demo_check(request, user):
-    if "welcome_code" in request.session:
+    if "welcome_code" not in request.session:
+        return
+
+    try:
         check = Check.objects.get(code=request.session["welcome_code"])
+    except Check.DoesNotExist:
+        return
 
-        # Only associate demo check if it doesn't have an owner already.
-        if check.user is None:
-            check.user = user
-            check.save()
+    # Only associate demo check if it doesn't have an owner already.
+    if check.user:
+        return
 
-            check.assign_all_channels()
+    check.user = user
+    check.save()
 
-            del request.session["welcome_code"]
+    check.assign_all_channels()
+
+    del request.session["welcome_code"]
 
 
 def login(request):