diff --git a/defaultstatus.php b/defaultstatus.php
index ec86ec0..425c9fc 100644
--- a/defaultstatus.php
+++ b/defaultstatus.php
@@ -76,7 +76,7 @@ switch ($action) {
             break;
         }
 
-        $message = get_string('deletecheckfull', '', get_string('variable', 'attendance'));
+        $message = get_string('deletecheckfull', 'attendance', get_string('variable', 'attendance'));
         $message .= str_repeat(html_writer::empty_tag('br'), 2);
         $message .= $status->acronym.': '.
             ($status->description ? $status->description : get_string('nodescription', 'attendance'));
diff --git a/lang/en/attendance.php b/lang/en/attendance.php
index d66899e..e831a53 100644
--- a/lang/en/attendance.php
+++ b/lang/en/attendance.php
@@ -132,6 +132,7 @@ $string['defaultview_desc'] = 'This is the default view shown to teachers on fir
 $string['delete'] = 'Delete';
 $string['deletewarningconfirm'] = 'Are you sure you want to delete this warning?';
 $string['deletedgroup'] = 'The group associated with this session has been deleted';
+$string['deletecheckfull'] = 'Are you absolutely sure you want to completely delete the {$a}, including all user data?';
 $string['deletehiddensessions'] = 'Delete all hidden sessions';
 $string['deletelogs'] = 'Delete attendance data';
 $string['deleteselected'] = 'Delete selected';
diff --git a/preferences.php b/preferences.php
index 3e6305e..9297f71 100644
--- a/preferences.php
+++ b/preferences.php
@@ -104,7 +104,7 @@ switch ($att->pageparams->action) {
             redirect($att->url_preferences(), get_string('statusdeleted', 'attendance'));
         }
 
-        $message = get_string('deletecheckfull', '', get_string('variable', 'attendance'));
+        $message = get_string('deletecheckfull', 'attendance', get_string('variable', 'attendance'));
         $message .= str_repeat(html_writer::empty_tag('br'), 2);
         $message .= $status->acronym.': '.
                     ($status->description ? $status->description : get_string('nodescription', 'attendance'));
diff --git a/sessions.php b/sessions.php
index 18ebfb0..67a3925 100644
--- a/sessions.php
+++ b/sessions.php
@@ -121,7 +121,7 @@ switch ($att->pageparams->action) {
 
         $sessinfo = $att->get_session_info($sessionid);
 
-        $message = get_string('deletecheckfull', '', get_string('session', 'attendance'));
+        $message = get_string('deletecheckfull', 'attendance', get_string('session', 'attendance'));
         $message .= str_repeat(html_writer::empty_tag('br'), 2);
         $message .= userdate($sessinfo->sessdate, get_string('strftimedmyhm', 'attendance'));
         $message .= html_writer::empty_tag('br');
@@ -136,7 +136,7 @@ switch ($att->pageparams->action) {
         exit;
     case mod_attendance_sessions_page_params::ACTION_DELETE_SELECTED:
         $confirm    = optional_param('confirm', null, PARAM_INT);
-        $message = get_string('deletecheckfull', '', get_string('session', 'attendance'));
+        $message = get_string('deletecheckfull', 'attendance', get_string('sessions', 'attendance'));
 
         if (isset($confirm) && confirm_sesskey()) {
             $sessionsids = required_param('sessionsids', PARAM_ALPHANUMEXT);