diff --git a/Sources/Helpers/DirectoryObserver.swift b/Sources/Helpers/DirectoryObserver.swift
index d060d313e0..9ffc5bf6c6 100644
--- a/Sources/Helpers/DirectoryObserver.swift
+++ b/Sources/Helpers/DirectoryObserver.swift
@@ -27,7 +27,7 @@ import Foundation
 }
 
 @objcMembers
-class DirectoryObserver: NSObject {
+final class DirectoryObserver: NSObject {
 
     static let updatedKey = "updated"
     static let deletedKey = "deleted"