diff --git a/Sources/QRScannerView.swift b/Sources/QRScannerView.swift
index 4a95d88..66cb004 100644
--- a/Sources/QRScannerView.swift
+++ b/Sources/QRScannerView.swift
@@ -155,22 +155,6 @@ class QRScannerWindowController: NSObject, AVCaptureMetadataOutputObjectsDelegat
         if session.canAddOutput(output) {
             session.addOutput(output)
             output.setMetadataObjectsDelegate(self, queue: .main)
-            // 检查摄像头是否支持 QR 码识别
-            if output.availableMetadataObjectTypes.contains(.qr) {
-                output.metadataObjectTypes = [.qr]
-                output.rectOfInterest = CGRect(x: 0.1, y: 0.1, width: 0.8, height: 0.8)
-            } else {
-                // fallback: 支持什么就用什么
-                let types = output.availableMetadataObjectTypes.filter { $0 == .qr || $0 == .ean13 || $0 == .ean8 || $0 == .code128 }
-                if !types.isEmpty {
-                    output.metadataObjectTypes = types
-                } else {
-                    DispatchQueue.main.async { [weak self] in
-                        self?.showError("Camera does not support QR code scanning")
-                    }
-                    return
-                }
-            }
         }
         
         let previewLayer = AVCaptureVideoPreviewLayer(session: session)
@@ -181,7 +165,6 @@ class QRScannerWindowController: NSObject, AVCaptureMetadataOutputObjectsDelegat
         // 回到主线程更新 UI
         DispatchQueue.main.async { [weak self] in
             guard let self = self, previewHost.window != nil else {
-                // 窗口已关闭，停止
                 session.stopRunning()
                 return
             }
@@ -196,6 +179,24 @@ class QRScannerWindowController: NSObject, AVCaptureMetadataOutputObjectsDelegat
             // 启动会话（后台启动避免阻塞）
             DispatchQueue.global(qos: .userInitiated).async {
                 session.startRunning()
+                
+                // session 启动后再设置 metadata types（启动前 availableMetadataObjectTypes 可能为空）
+                if session.canAddOutput(output) == false,
+                   output.availableMetadataObjectTypes.contains(.qr) {
+                    output.metadataObjectTypes = [.qr]
+                } else {
+                    // 尝试设置所有支持的类型
+                    let available = output.availableMetadataObjectTypes
+                    if available.contains(.qr) {
+                        output.metadataObjectTypes = [.qr]
+                    } else if !available.isEmpty {
+                        output.metadataObjectTypes = available
+                    } else {
+                        DispatchQueue.main.async { [weak self] in
+                            self?.showError("Camera does not support QR scanning. Check System Settings → Privacy → Camera.")
+                        }
+                    }
+                }
             }
         }
     }