diff --git a/.semver.txt b/.semver.txt
index c2320f5..b112f91 100644
--- a/.semver.txt
+++ b/.semver.txt
@@ -1 +1 @@
-1.0.20
+1.0.21
diff --git a/src/MonsterMonitor/MonsterMonitor.csproj b/src/MonsterMonitor/MonsterMonitor.csproj
index 950745e..14abc3d 100644
--- a/src/MonsterMonitor/MonsterMonitor.csproj
+++ b/src/MonsterMonitor/MonsterMonitor.csproj
@@ -6,10 +6,10 @@
     <LangVersion>7.3</LangVersion>
     <RootNamespace>MonsterMonitor</RootNamespace>
     <AssemblyName>devenv</AssemblyName>
-    <AssemblyVersion>1.0.20</AssemblyVersion>
-    <Version>1.0.20</Version>
-    <FileVersion>1.0.20</FileVersion>
-    <InformationalVersion>1.0.20</InformationalVersion>
+    <AssemblyVersion>1.0.21</AssemblyVersion>
+    <Version>1.0.21</Version>
+    <FileVersion>1.0.21</FileVersion>
+    <InformationalVersion>1.0.21</InformationalVersion>
   </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="Costura.Fody" Version="6.0.0">
diff --git a/src/MonsterMonitor/Program.cs b/src/MonsterMonitor/Program.cs
index b126fbe..183628d 100644
--- a/src/MonsterMonitor/Program.cs
+++ b/src/MonsterMonitor/Program.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Threading;
 using System.Windows.Forms;
 using MonsterMonitor.UI;
 
@@ -6,9 +7,21 @@ namespace MonsterMonitor
 {
     internal static class Program
     {
+        private const string SingleInstanceMutexName = @"Global\MonsterMonitor_v2_SingleInstance";
+        private const string ActivateEventName = @"Global\MonsterMonitor_v2_Activate";
+
         [STAThread]
         private static void Main()
         {
+            var createdNew = false;
+            using (var mutex = new Mutex(true, SingleInstanceMutexName, out createdNew))
+            {
+                if (!createdNew)
+                {
+                    TrySignalExistingInstance();
+                    return;
+                }
+
             Application.ThreadException += (sender, args) =>
             {
                 MessageBox.Show(
@@ -29,7 +42,38 @@ namespace MonsterMonitor
 
             Application.EnableVisualStyles();
             Application.SetCompatibleTextRenderingDefault(false);
-            Application.Run(new MainForm());
+                using (var activateEvent = new EventWaitHandle(false, EventResetMode.AutoReset, ActivateEventName))
+                {
+                    var form = new MainForm();
+                    ThreadPool.RegisterWaitForSingleObject(
+                        activateEvent,
+                        (state, timedOut) =>
+                        {
+                            var mainForm = state as MainForm;
+                            mainForm?.RestoreAndActivateFromExternalSignal();
+                        },
+                        form,
+                        Timeout.Infinite,
+                        false);
+
+                    Application.Run(form);
+                }
+            }
+        }
+
+        private static void TrySignalExistingInstance()
+        {
+            try
+            {
+                using (var activateEvent = EventWaitHandle.OpenExisting(ActivateEventName))
+                {
+                    activateEvent.Set();
+                }
+            }
+            catch
+            {
+                // Если не удалось отправить сигнал, просто завершаем второй инстанс.
+            }
         }
     }
 }
diff --git a/src/MonsterMonitor/UI/MainForm.cs b/src/MonsterMonitor/UI/MainForm.cs
index a88b6c3..081f158 100644
--- a/src/MonsterMonitor/UI/MainForm.cs
+++ b/src/MonsterMonitor/UI/MainForm.cs
@@ -135,6 +135,33 @@ namespace MonsterMonitor.UI
             Activate();
         }
 
+        public void RestoreAndActivateFromExternalSignal()
+        {
+            if (InvokeRequired)
+            {
+                BeginInvoke(new Action(RestoreAndActivateFromExternalSignal));
+                return;
+            }
+
+            _log.Info("Получен сигнал активации от второго инстанса.");
+
+            if (!Visible)
+            {
+                Show();
+            }
+
+            if (WindowState == FormWindowState.Minimized)
+            {
+                WindowState = FormWindowState.Normal;
+            }
+
+            // Небольшой трюк для надежного вывода окна на передний план.
+            TopMost = true;
+            Activate();
+            TopMost = false;
+            Focus();
+        }
+
         private void ExitApplication()
         {
             _allowClose = true;