diff --git a/htdocs/comm/propal/class/propal.class.php b/htdocs/comm/propal/class/propal.class.php
index de67b9c78de..990af29d90f 100644
--- a/htdocs/comm/propal/class/propal.class.php
+++ b/htdocs/comm/propal/class/propal.class.php
@@ -2056,7 +2056,7 @@ class Propal extends CommonObject
                     {
                         // We remove directory
                         $ref = dol_sanitizeFileName($this->ref);
-                        if ($conf->propal->dir_output)
+                        if ($conf->propal->dir_output && !empty($this->ref))
                         {
                             $dir = $conf->propal->dir_output . "/" . $ref ;
                             $file = $dir . "/" . $ref . ".pdf";
diff --git a/htdocs/commande/class/commande.class.php b/htdocs/commande/class/commande.class.php
index 27503790375..a2225b033b8 100644
--- a/htdocs/commande/class/commande.class.php
+++ b/htdocs/commande/class/commande.class.php
@@ -2457,7 +2457,7 @@ class Commande extends CommonOrder
 
         	// On efface le repertoire de pdf provisoire
         	$comref = dol_sanitizeFileName($this->ref);
-        	if ($conf->commande->dir_output)
+        	if ($conf->commande->dir_output && !empty($this->ref))
         	{
         		$dir = $conf->commande->dir_output . "/" . $comref ;
         		$file = $conf->commande->dir_output . "/" . $comref . "/" . $comref . ".pdf";
diff --git a/htdocs/compta/facture/class/facture.class.php b/htdocs/compta/facture/class/facture.class.php
index 461b3606cd6..80911290521 100644
--- a/htdocs/compta/facture/class/facture.class.php
+++ b/htdocs/compta/facture/class/facture.class.php
@@ -1323,7 +1323,7 @@ class Facture extends CommonInvoice
 				{
 					// On efface le repertoire de pdf provisoire
 					$ref = dol_sanitizeFileName($this->ref);
-					if ($conf->facture->dir_output)
+					if ($conf->facture->dir_output && !empty($this->ref))
 					{
 						$dir = $conf->facture->dir_output . "/" . $ref;
 						$file = $conf->facture->dir_output . "/" . $ref . "/" . $ref . ".pdf";