diff --git a/htdocs/compta/facture/card.php b/htdocs/compta/facture/card.php
index bf84114129f..0e09e5570e9 100644
--- a/htdocs/compta/facture/card.php
+++ b/htdocs/compta/facture/card.php
@@ -3251,8 +3251,7 @@ if ($action == 'create')
 		print '<tr><td>' . $langs->trans($newclassname) . '</td><td colspan="2">' . $objectsrc->getNomUrl(1);
 		// We check if Origin document (id and type is known) has already at least one invoice attached to it
 		$objectsrc->fetchObjectLinked($originid,$origin,'','facture');
-		$cntinvoice=count($objectsrc->linkedObjects['facture']);
-		if ($cntinvoice>=1)
+		if (is_array($objectsrc->linkedObjects['facture']) && count($objectsrc->linkedObjects['facture']) >= 1)
 		{
 			setEventMessages('WarningBillExist', null, 'warnings');
 			echo ' ('.$langs->trans('LatestRelatedBill').end($objectsrc->linkedObjects['facture'])->getNomUrl(1).')';