diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index af61871922959c027e7224c8f7ee202141e04bd0..e5c27516ad3c11bc433c33d63eac8c65b6442f55 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -14,6 +14,11 @@ Changed
 
 * Use start date of current SchoolTerm as default value for PersonalNote filter in overview.
 
+Fixed
+~~~~~
+
+* Events without groups caused an error when not accessed through the week view.
+
 `2.0rc7` - 2021-12-25
 ---------------------
 
diff --git a/aleksis/apps/alsijil/templates/alsijil/class_register/lesson.html b/aleksis/apps/alsijil/templates/alsijil/class_register/lesson.html
index 9a55603ef3f7857b9fc8e5b85c4059518dedc46e..08af12a757d7377747075f5952cc380e5f300595 100644
--- a/aleksis/apps/alsijil/templates/alsijil/class_register/lesson.html
+++ b/aleksis/apps/alsijil/templates/alsijil/class_register/lesson.html
@@ -50,7 +50,7 @@
   {% has_perm "alsijil.edit_lessondocumentation_rule" user register_object as can_edit_lesson_documentation %}
   {% has_perm "alsijil.edit_register_object_personalnote_rule" user register_object as can_edit_register_object_personalnote %}
 
-  {% if next_lesson_person or prev_lesson_person or lesson_documentation %}
+  {% if next_lesson_person or prev_lesson_person or back_to_week_url %}
     <div class="row margin-bottom z-depth-1 alsijil-nav-header">
       <div class="col s12 no-padding">
         {# Back to week view #}
diff --git a/aleksis/apps/alsijil/views.py b/aleksis/apps/alsijil/views.py
index 1fe31fd271c6725c374bf695103c73b733dde54d..ccb11c6da46750780bf06e987407627f35690e5d 100644
--- a/aleksis/apps/alsijil/views.py
+++ b/aleksis/apps/alsijil/views.py
@@ -293,7 +293,7 @@ def register_object(
         )
         if back_url_is_safe:
             context["back_to_week_url"] = back_url
-        else:
+        elif register_object.get_groups().all():
             context["back_to_week_url"] = reverse(
                 "week_view_by_week",
                 args=[