diff --git a/classes/Tools.php b/classes/Tools.php
index 4eb8fb0a2..eb549d93d 100644
--- a/classes/Tools.php
+++ b/classes/Tools.php
@@ -2178,6 +2178,19 @@ FileETag INode MTime Size
 
 		return false;
 	}
+	
+	/**
+	 * Reproduce array_unique working before php version 5.2.9 
+	 * @param array $array
+	 * @return array
+	 */
+	public static function arrayUnique($array)
+	{
+		if (version_compare(phpversion(), '5.2.9', '<'))
+			return array_unique($array);
+		else
+			return array_unique($array, SORT_REGULAR);
+	}
 }
 
 /**
diff --git a/controllers/admin/AdminProductsController.php b/controllers/admin/AdminProductsController.php
index 2d8679a92..21c50ac92 100644
--- a/controllers/admin/AdminProductsController.php
+++ b/controllers/admin/AdminProductsController.php
@@ -3567,7 +3567,7 @@ class AdminProductsControllerCore extends AdminController
 					if ($ws)
 						$warehouses[] = $ws;
 				}
-				$warehouses = array_unique($warehouses);
+				$warehouses = Tools::arrayUnique($warehouses);
 
 				if (empty($warehouses))
 					$advanced_stock_management_warning = true;