diff --git a/htdocs/core/class/html.formticket.class.php b/htdocs/core/class/html.formticket.class.php
index cba880dfada..97d4c5d3954 100644
--- a/htdocs/core/class/html.formticket.class.php
+++ b/htdocs/core/class/html.formticket.class.php
@@ -1211,7 +1211,7 @@ class FormTicket
 			dol_delete_dir_recursive($upload_dir);
 		}
 
-		$keytoavoidconflict = empty($this->trackid) ? '' : '-'.$this->trackid; // this->trackid must be defined
+		$keytoavoidconflict = empty($this->track_id) ? '' : '-'.$this->track_id; // track_id instead of trackid
 		unset($_SESSION["listofpaths".$keytoavoidconflict]);
 		unset($_SESSION["listofnames".$keytoavoidconflict]);
 		unset($_SESSION["listofmimes".$keytoavoidconflict]);
@@ -1269,7 +1269,7 @@ class FormTicket
 		$listofpaths = array();
 		$listofnames = array();
 		$listofmimes = array();
-		$keytoavoidconflict = empty($this->trackid) ? '' : '-'.$this->trackid; // this->trackid must be defined
+		$keytoavoidconflict = empty($this->track_id) ? '' : '-'.$this->track_id; // track_id instead of trackid
 
 		if (GETPOST('mode', 'alpha') == 'init' || (GETPOST('modelmailselected', 'alpha') && GETPOST('modelmailselected', 'alpha') != '-1')) {
 			if (!empty($arraydefaultmessage->joinfiles) && is_array($this->param['fileinit'])) {