diff --git a/Leaf.Core/Extensions/System/DateTimeExtensions.cs b/Leaf.Core/Extensions/System/DateTimeExtensions.cs
index 6d8572f..3670dc6 100644
--- a/Leaf.Core/Extensions/System/DateTimeExtensions.cs
+++ b/Leaf.Core/Extensions/System/DateTimeExtensions.cs
@@ -23,7 +23,7 @@ public static DateTime FirstJanuary1970
         /// </summary>
         public static string ToFileFormatString(this DateTime self)
         {
-            return self.ToString("yyyy-MM-dd__HH:mm:ss", CultureInfo.InvariantCulture);
+            return self.ToString("yyyy-MM-dd__HH-mm-ss", CultureInfo.InvariantCulture);
         }
     }
 }
\ No newline at end of file