diff --git a/MainForm.cs b/MainForm.cs
index 0d7fef1..e044255 100644
--- a/MainForm.cs
+++ b/MainForm.cs
@@ -2,6 +2,7 @@ using System;
 using System.Drawing;
 using System.Runtime.InteropServices;
 using System.Windows.Forms;
+using Microsoft.Win32;
 
 namespace TimerApp
 {
@@ -129,6 +130,8 @@ namespace TimerApp
 
             _monitor.Start();
 
+            SystemEvents.PowerModeChanged += OnPowerModeChanged;
+
             // Set tray icon
             try
             {
@@ -550,6 +553,7 @@ namespace TimerApp
             }
             else
             {
+                SystemEvents.PowerModeChanged -= OnPowerModeChanged;
                 notifyIcon1.Visible = false;
                 notifyIcon1.Dispose();
             }
@@ -615,5 +619,15 @@ namespace TimerApp
         {
             this.WindowState = FormWindowState.Minimized;
         }
+
+        private void OnPowerModeChanged(object sender, PowerModeChangedEventArgs e)
+        {
+            if (e.Mode == PowerModes.Resume)
+            {
+                // 系统唤醒时，强制重置媒体播放检测状态，
+                // 避免因检测线程挂起导致一直误报“正在播放”而无法进入工作状态。
+                NativeMethods.InvalidateMediaCache();
+            }
+        }
     }
 }
diff --git a/NativeMethods.cs b/NativeMethods.cs
index 5321aab..0421e3f 100644
--- a/NativeMethods.cs
+++ b/NativeMethods.cs
@@ -57,6 +57,18 @@ namespace TimerApp
             return Volatile.Read(ref _mediaPlaying);
         }
 
+        /// <summary>
+        /// 强制失效媒体播放状态缓存
+        /// </summary>
+        public static void InvalidateMediaCache()
+        {
+            Interlocked.Exchange(ref _mediaLastUpdateMs, -1);
+            // 不直接重置 _mediaPlaying，以免在检测过程中出现闪烁，
+            // 只是强制下一次 IsMediaPlaying 触发新的检测。
+            // 但如果处于 Resume 状态，假设不播放是安全的。
+            Volatile.Write(ref _mediaPlaying, false);
+        }
+
         private static bool _mediaPlaying;
         private static long _mediaLastUpdateMs = -1;
         private static int _mediaUpdateInProgress;
@@ -256,7 +268,12 @@ namespace TimerApp
             thread.IsBackground = true;
             thread.SetApartmentState(ApartmentState.STA);
             thread.Start();
-            thread.Join();
+            
+            // Wait with timeout (e.g. 2 seconds) to prevent hanging
+            if (!thread.Join(2000))
+            {
+                return false;
+            }
 
             if (error is not null)
             {