diff --git a/add_form.php b/add_form.php
index f216caa..0953b56 100644
--- a/add_form.php
+++ b/add_form.php
@@ -195,6 +195,9 @@ class mod_attendance_add_form extends moodleform {
                 $errors['sdays'] = get_string('checkweekdays', 'attendance');
             }
         }
+        if ($addmulti && ceil(($data['sessionenddate'] - $data['sessiondate']) / YEARSECS) > 1) {
+            $errors['sessionenddate'] = get_string('timeahead', 'attendance');
+        }
         return $errors;
     }
 
diff --git a/lang/en/attendance.php b/lang/en/attendance.php
index 4375926..f338c53 100644
--- a/lang/en/attendance.php
+++ b/lang/en/attendance.php
@@ -308,3 +308,5 @@ $string['notmember'] = 'not member';
 $string['deletehiddensessions'] = 'Delete all hidden sessions';
 $string['confirmdeletehiddensessions'] = 'Are you sure you want to delete {$a->count} sessions scheduled before the course start date ({$a->date})?';
 $string['hiddensessionsdeleted'] = 'All hidden sessions were delete';
+
+$string['timeahead'] = 'Must not exceed one year ahead of the session date';