diff --git a/mac/sound.cpp b/mac/sound.cpp
index 049ac213..3392c00d 100755
--- a/mac/sound.cpp
+++ b/mac/sound.cpp
@@ -161,6 +161,12 @@ CSound::CSound ( void (*fpNewProcessCallback) ( CVector<short>& psData, void* ar
     lCurDev                    = INVALID_SNC_CARD_DEVICE;
     CurrentAudioInputDeviceID  = 0;
     CurrentAudioOutputDeviceID = 0;
+    iNumInChan                 = 0;
+    iNumOutChan                = 0;
+    iSelInputLeftChannel       = 0;
+    iSelInputRightChannel      = 0;
+    iSelOutputLeftChannel      = 0;
+    iSelOutputRightChannel     = 0;
 }
 
 void CSound::GetAudioDeviceInfos ( const AudioDeviceID DeviceID,
diff --git a/src/clientsettingsdlg.cpp b/src/clientsettingsdlg.cpp
index e940d37a..c5fa6d4f 100755
--- a/src/clientsettingsdlg.cpp
+++ b/src/clientsettingsdlg.cpp
@@ -542,8 +542,11 @@ void CClientSettingsDlg::UpdateSoundChannelSelectionFrame()
             cbxLInChan->addItem ( pClient->GetSndCrdInputChannelName ( iSndChanIdx ) );
             cbxRInChan->addItem ( pClient->GetSndCrdInputChannelName ( iSndChanIdx ) );
         }
-        cbxLInChan->setCurrentIndex ( pClient->GetSndCrdLeftInputChannel() );
-        cbxRInChan->setCurrentIndex ( pClient->GetSndCrdRightInputChannel() );
+        if ( pClient->GetSndCrdNumInputChannels() > 0 )
+        {
+            cbxLInChan->setCurrentIndex ( pClient->GetSndCrdLeftInputChannel() );
+            cbxRInChan->setCurrentIndex ( pClient->GetSndCrdRightInputChannel() );
+        }
 
         // output
         cbxLOutChan->clear();
@@ -553,8 +556,11 @@ void CClientSettingsDlg::UpdateSoundChannelSelectionFrame()
             cbxLOutChan->addItem ( pClient->GetSndCrdOutputChannelName ( iSndChanIdx ) );
             cbxROutChan->addItem ( pClient->GetSndCrdOutputChannelName ( iSndChanIdx ) );
         }
-        cbxLOutChan->setCurrentIndex ( pClient->GetSndCrdLeftOutputChannel() );
-        cbxROutChan->setCurrentIndex ( pClient->GetSndCrdRightOutputChannel() );
+        if ( pClient->GetSndCrdNumOutputChannels() > 0 )
+        {
+            cbxLOutChan->setCurrentIndex ( pClient->GetSndCrdLeftOutputChannel() );
+            cbxROutChan->setCurrentIndex ( pClient->GetSndCrdRightOutputChannel() );
+        }
     }
 #else
     // for other OS, no sound card channel selection is supported