diff --git a/MainForm.cs b/MainForm.cs
index 6da352e..890bc0d 100644
--- a/MainForm.cs
+++ b/MainForm.cs
@@ -25,7 +25,7 @@ namespace PDF_Merge
         }
         public void SetPathLable()
         {
-            string sourcePath = ConfigurationManager.AppSettings["PDF-Path"];
+            string sourcePath = ConfigurationManager.AppSettings["PDF-Path"] ?? "";
             
             if (sourcePath != null)
             {