diff --git a/htdocs/install/inc.php b/htdocs/install/inc.php
index 657e9841100..c717d55850e 100644
--- a/htdocs/install/inc.php
+++ b/htdocs/install/inc.php
@@ -319,7 +319,7 @@ function conf($dolibarr_main_document_root)
 	$conf->db->port = trim($dolibarr_main_db_port);
 	$conf->db->name = trim($dolibarr_main_db_name);
 	$conf->db->user = trim($dolibarr_main_db_user);
-	$conf->db->pass = trim($dolibarr_main_db_pass);
+	$conf->db->pass = (empty($dolibarr_main_db_pass) ? '' : trim($dolibarr_main_db_pass));
 
 	// Mysql driver support has been removed in favor of mysqli
 	if ($conf->db->type == 'mysql') {
diff --git a/htdocs/install/upgrade.php b/htdocs/install/upgrade.php
index 25dd1ee84fd..22ef26295aa 100644
--- a/htdocs/install/upgrade.php
+++ b/htdocs/install/upgrade.php
@@ -117,9 +117,9 @@ if (!GETPOST('action', 'aZ09') || preg_match('/upgrade/i', GETPOST('action', 'aZ
 	$error = 0;
 
 	// If password is encoded, we decode it
-	if (preg_match('/crypted:/i', $dolibarr_main_db_pass) || !empty($dolibarr_main_db_encrypted_pass)) {
+	if ((!empty($dolibarr_main_db_pass) && preg_match('/crypted:/i', $dolibarr_main_db_pass)) || !empty($dolibarr_main_db_encrypted_pass)) {
 		require_once $dolibarr_main_document_root.'/core/lib/security.lib.php';
-		if (preg_match('/crypted:/i', $dolibarr_main_db_pass)) {
+		if (!empty($dolibarr_main_db_pass) && preg_match('/crypted:/i', $dolibarr_main_db_pass)) {
 			$dolibarr_main_db_pass = preg_replace('/crypted:/i', '', $dolibarr_main_db_pass);
 			$dolibarr_main_db_pass = dol_decode($dolibarr_main_db_pass);
 			$dolibarr_main_db_encrypted_pass = $dolibarr_main_db_pass; // We need to set this as it is used to know the password was initially crypted