diff --git a/juce_amalgamated.cpp b/juce_amalgamated.cpp
index c6fbbbc130..7bc5db5068 100644
--- a/juce_amalgamated.cpp
+++ b/juce_amalgamated.cpp
@@ -250506,6 +250506,7 @@ const String DSoundAudioIODevice::openDevice (const BigInteger& inputChannels,
 							false);
 
 	inputBuffers.setSize (jmax (1, enabledInputs.countNumberOfSetBits()), bufferSizeSamples);
+	inputBuffers.clear();
 	int i, numIns = 0;
 
 	for (i = 0; i <= enabledInputs.getHighestBit(); i += 2)
@@ -250531,6 +250532,7 @@ const String DSoundAudioIODevice::openDevice (const BigInteger& inputChannels,
 							 false);
 
 	outputBuffers.setSize (jmax (1, enabledOutputs.countNumberOfSetBits()), bufferSizeSamples);
+	outputBuffers.clear();
 	int numOuts = 0;
 
 	for (i = 0; i <= enabledOutputs.getHighestBit(); i += 2)
diff --git a/src/native/windows/juce_win32_DirectSound.cpp b/src/native/windows/juce_win32_DirectSound.cpp
index 8872efdd46..7b8903a76d 100644
--- a/src/native/windows/juce_win32_DirectSound.cpp
+++ b/src/native/windows/juce_win32_DirectSound.cpp
@@ -1468,6 +1468,7 @@ const String DSoundAudioIODevice::openDevice (const BigInteger& inputChannels,
                             false);
 
     inputBuffers.setSize (jmax (1, enabledInputs.countNumberOfSetBits()), bufferSizeSamples);
+    inputBuffers.clear();
     int i, numIns = 0;
 
     for (i = 0; i <= enabledInputs.getHighestBit(); i += 2)
@@ -1493,6 +1494,7 @@ const String DSoundAudioIODevice::openDevice (const BigInteger& inputChannels,
                              false);
 
     outputBuffers.setSize (jmax (1, enabledOutputs.countNumberOfSetBits()), bufferSizeSamples);
+    outputBuffers.clear();
     int numOuts = 0;
 
     for (i = 0; i <= enabledOutputs.getHighestBit(); i += 2)