diff --git a/DHSoftware/LoginWindow.cs b/DHSoftware/LoginWindow.cs
index 29ab6f2..b4a6b85 100644
--- a/DHSoftware/LoginWindow.cs
+++ b/DHSoftware/LoginWindow.cs
@@ -25,7 +25,7 @@ namespace DHSoftware
         {
             get
             {
-                if (_instance == null)
+                if (_instance == null || _instance.IsDisposed)
                     _instance = new LoginWindow();
                 return _instance;
             }
diff --git a/DHSoftware/Views/SettingWindow.cs b/DHSoftware/Views/SettingWindow.cs
index 2719ab0..35b584c 100644
--- a/DHSoftware/Views/SettingWindow.cs
+++ b/DHSoftware/Views/SettingWindow.cs
@@ -27,7 +27,7 @@ namespace DHSoftware.Views
         {
             get
             {
-                if (_instance == null)
+                if (_instance == null || _instance.IsDisposed)
                     _instance = new SettingWindow();
                 return _instance;
             }