diff --git a/ISCamRecorder/ISCamera.cs b/ISCamRecorder/ISCamera.cs
index 396cdf7..a154853 100644
--- a/ISCamRecorder/ISCamera.cs
+++ b/ISCamRecorder/ISCamera.cs
@@ -51,10 +51,7 @@
             if (_Cam.DeviceValid) return true;
 
             // 接続
-            var devices = _Cam.Devices;
-            //if (!devices.Any(c => c.GetSerialNumber().Equals(_SerialNumber))) return false;
-            //if (devices.Length<1) return false;
-            var dev = devices.FirstOrDefault(
+            var dev = _Cam.Devices.FirstOrDefault(
                 c => c.GetSerialNumber().Equals(_SerialNumber));
             if (dev == null) return false;
             _Cam.Device = dev;
@@ -98,6 +95,7 @@
         /// </summary>
         /// <param name="isRec">true:録画 false:プレビュー</param>
         public void ChangeSink(bool isRec) {
+            if (!_Cam.DeviceValid) return;
             _Cam.LiveStop();
             if (isRec) _Cam.Sink = _RecSink;
             else _Cam.Sink = _PreviewSink;
@@ -108,6 +106,7 @@
         /// 画像撮影
         /// </summary>
         public void SnapImage() {
+            if (!_Cam.DeviceValid) return;
             TIS.Imaging.FrameSnapSink snapSink = new TIS.Imaging.FrameSnapSink();
             _Cam.LiveStop();
             _Cam.Sink = snapSink;
@@ -137,6 +136,7 @@
         /// 録画
         /// </summary>
         public void RecordToMemory(float recodingLimit) {
+            if (!_Cam.DeviceValid) return;
             Debug.WriteLine($"{_CamID} starts recoding.");
             _Recoding = true;
             ClearBuffer();
@@ -158,6 +158,7 @@
         /// </summary>
         /// <param name="outDir"></param>
         public void SaveToFile() {
+            if (!_Cam.DeviceValid) return;
             Debug.WriteLine($"{_CamID} starts saving with {CameraFPS}fps.");
             // 保存先確保
             var outDir2 = Path.Combine(_MF.OutputDir, _CamID);
@@ -252,6 +253,7 @@
         /// </summary>
         /// <param name="enable"></param>
         public void SetTriggerMode(bool enable) {
+            if (!_Cam.DeviceValid) return;
             _Cam.LiveStop();
             _Cam.DeviceTrigger = enable;
             _Cam.LiveStart();
diff --git a/ISCamRecorder/SensorData.cs b/ISCamRecorder/SensorData.cs
index 9dbe590..be466d8 100644
--- a/ISCamRecorder/SensorData.cs
+++ b/ISCamRecorder/SensorData.cs
@@ -59,8 +59,12 @@
             // シリアルポート接続 
             var portname = GetSerialPort();
             if (portname.Length < 1) {
+#if DEBUG
+                Debug.WriteLine($"No Serial Connection.");
+#else
                 MessageBox.Show("シリアルデバイスに接続できません", "Error",
                     MessageBoxButtons.OK, MessageBoxIcon.Warning);
+#endif
                 return false;
             }
             _Serial = new SerialPort {
@@ -81,7 +85,7 @@
                 Debug.WriteLine(ex.Message);
                 return false;
             }
-            Debug.WriteLine($"Serial Connect {portname}");
+            Debug.WriteLine($"Serial Connect {portname}.");
             return true;
         }