diff --git a/reactos/include/reactos/libs/sound/mmebuddy.h b/reactos/include/reactos/libs/sound/mmebuddy.h
index 4e1583230c1..cae6f3f1489 100644
--- a/reactos/include/reactos/libs/sound/mmebuddy.h
+++ b/reactos/include/reactos/libs/sound/mmebuddy.h
@@ -400,8 +400,8 @@ ReleaseEntrypointMutex(
 VOID
 NotifyMmeClient(
     IN  PSOUND_DEVICE_INSTANCE SoundDeviceInstance,
-    IN  DWORD Message,
-    IN  DWORD Parameter);
+    IN  UINT Message,
+    IN  DWORD_PTR Parameter);
 
 MMRESULT
 MmeGetSoundDeviceCapabilities(
@@ -413,20 +413,20 @@ MmeGetSoundDeviceCapabilities(
 MMRESULT
 MmeOpenWaveDevice(
     IN  MMDEVICE_TYPE DeviceType,
-    IN  DWORD DeviceId,
+    IN  UINT DeviceId,
     IN  LPWAVEOPENDESC OpenParameters,
     IN  DWORD Flags,
-    OUT DWORD* PrivateHandle);
+    OUT DWORD_PTR* PrivateHandle);
 
 MMRESULT
 MmeCloseDevice(
-    IN  DWORD PrivateHandle);
+    IN  DWORD_PTR PrivateHandle);
 
 MMRESULT
 MmeGetPosition(
     IN  MMDEVICE_TYPE DeviceType,
     IN  DWORD DeviceId,
-    IN  DWORD PrivateHandle,
+    IN  DWORD_PTR PrivateHandle,
     IN  MMTIME* Time,
     IN  DWORD Size);
 
@@ -441,7 +441,7 @@ MmeGetDeviceInterfaceString(
 
 MMRESULT
 MmeSetState(
-    IN  DWORD PrivateHandle,
+    IN  DWORD_PTR PrivateHandle,
     IN  BOOL bStart);
 
 
@@ -456,7 +456,7 @@ MmeSetState(
 
 MMRESULT
 MmeResetWavePlayback(
-    IN  DWORD PrivateHandle);
+    IN  DWORD_PTR PrivateHandle);
 
 
 /*
diff --git a/reactos/lib/drivers/sound/mmebuddy/auxiliary/auxMessage.c b/reactos/lib/drivers/sound/mmebuddy/auxiliary/auxMessage.c
index f248a48e400..9cfa0d941e6 100644
--- a/reactos/lib/drivers/sound/mmebuddy/auxiliary/auxMessage.c
+++ b/reactos/lib/drivers/sound/mmebuddy/auxiliary/auxMessage.c
@@ -24,11 +24,11 @@
 DWORD
 APIENTRY
 auxMessage(
-    DWORD DeviceId,
-    DWORD Message,
-    DWORD PrivateHandle,
-    DWORD Parameter1,
-    DWORD Parameter2)
+    UINT DeviceId,
+    UINT Message,
+    DWORD_PTR PrivateHandle,
+    DWORD_PTR Parameter1,
+    DWORD_PTR Parameter2)
 {
     MMRESULT Result = MMSYSERR_NOTSUPPORTED;
 
diff --git a/reactos/lib/drivers/sound/mmebuddy/midi/midMessage.c b/reactos/lib/drivers/sound/mmebuddy/midi/midMessage.c
index a99b6dc29ad..9e1a0ec24f6 100644
--- a/reactos/lib/drivers/sound/mmebuddy/midi/midMessage.c
+++ b/reactos/lib/drivers/sound/mmebuddy/midi/midMessage.c
@@ -24,11 +24,11 @@
 DWORD
 APIENTRY
 midMessage(
-    DWORD DeviceId,
-    DWORD Message,
-    DWORD PrivateHandle,
-    DWORD Parameter1,
-    DWORD Parameter2)
+    UINT DeviceId,
+    UINT Message,
+    DWORD_PTR PrivateHandle,
+    DWORD_PTR Parameter1,
+    DWORD_PTR Parameter2)
 {
     MMRESULT Result = MMSYSERR_NOTSUPPORTED;
 
diff --git a/reactos/lib/drivers/sound/mmebuddy/midi/modMessage.c b/reactos/lib/drivers/sound/mmebuddy/midi/modMessage.c
index bde698719e4..febfca516b5 100644
--- a/reactos/lib/drivers/sound/mmebuddy/midi/modMessage.c
+++ b/reactos/lib/drivers/sound/mmebuddy/midi/modMessage.c
@@ -24,11 +24,11 @@
 DWORD
 APIENTRY
 modMessage(
-    DWORD DeviceId,
-    DWORD Message,
-    DWORD PrivateHandle,
-    DWORD Parameter1,
-    DWORD Parameter2)
+    UINT DeviceId,
+    UINT Message,
+    DWORD_PTR PrivateHandle,
+    DWORD_PTR Parameter1,
+    DWORD_PTR Parameter2)
 {
     MMRESULT Result = MMSYSERR_NOTSUPPORTED;
 
diff --git a/reactos/lib/drivers/sound/mmebuddy/mixer/mxdMessage.c b/reactos/lib/drivers/sound/mmebuddy/mixer/mxdMessage.c
index 86e63773c0e..cf870540ba1 100644
--- a/reactos/lib/drivers/sound/mmebuddy/mixer/mxdMessage.c
+++ b/reactos/lib/drivers/sound/mmebuddy/mixer/mxdMessage.c
@@ -20,10 +20,10 @@
 
 MMRESULT
 MmeGetLineInfo(
-    IN  DWORD Message,
-    IN  DWORD PrivateHandle,
-    IN  DWORD Parameter1,
-    IN  DWORD Parameter2)
+    IN  UINT Message,
+    IN  DWORD_PTR PrivateHandle,
+    IN  DWORD_PTR Parameter1,
+    IN  DWORD_PTR Parameter2)
 {
     MMRESULT Result;
     PSOUND_DEVICE_INSTANCE SoundDeviceInstance;
@@ -54,7 +54,7 @@ MmeGetLineInfo(
 
 MMRESULT
 MmeCloseMixerDevice(
-    IN  DWORD PrivateHandle)
+    IN  DWORD_PTR PrivateHandle)
 {
     MMRESULT Result;
     PSOUND_DEVICE_INSTANCE SoundDeviceInstance;
@@ -122,7 +122,7 @@ MmeOpenMixerDevice(
     }
 
     /* Store the device instance pointer in the private handle - is DWORD safe here? */
-    *PrivateHandle = (DWORD) SoundDeviceInstance;
+    *PrivateHandle = (DWORD_PTR) SoundDeviceInstance;
 
     /* Store the additional information we were given - FIXME: Need flags! */
     SetSoundDeviceInstanceMmeData(SoundDeviceInstance,
@@ -151,11 +151,11 @@ MmeOpenMixerDevice(
 DWORD
 APIENTRY
 mxdMessage(
-    DWORD DeviceId,
-    DWORD Message,
-    DWORD PrivateHandle,
-    DWORD Parameter1,
-    DWORD Parameter2)
+    UINT DeviceId,
+    UINT Message,
+    DWORD_PTR PrivateHandle,
+    DWORD_PTR Parameter1,
+    DWORD_PTR Parameter2)
 {
     MMRESULT Result = MMSYSERR_NOTSUPPORTED;
 
diff --git a/reactos/lib/drivers/sound/mmebuddy/mmewrap.c b/reactos/lib/drivers/sound/mmebuddy/mmewrap.c
index 63f3e6f5c5a..960c4839a50 100644
--- a/reactos/lib/drivers/sound/mmebuddy/mmewrap.c
+++ b/reactos/lib/drivers/sound/mmebuddy/mmewrap.c
@@ -22,7 +22,7 @@
 
 MMRESULT
 MmeSetState(
-    IN  DWORD PrivateHandle,
+    IN  DWORD_PTR PrivateHandle,
     IN  BOOL bStart)
 {
     MMRESULT Result;
@@ -64,8 +64,8 @@ MmeSetState(
 VOID
 NotifyMmeClient(
     IN  PSOUND_DEVICE_INSTANCE SoundDeviceInstance,
-    IN  DWORD Message,
-    IN  DWORD Parameter)
+    IN  UINT Message,
+    IN  DWORD_PTR Parameter)
 {
     SND_ASSERT( SoundDeviceInstance );
 
@@ -121,10 +121,10 @@ MmeGetSoundDeviceCapabilities(
 MMRESULT
 MmeOpenWaveDevice(
     IN  MMDEVICE_TYPE DeviceType,
-    IN  DWORD DeviceId,
+    IN  UINT DeviceId,
     IN  LPWAVEOPENDESC OpenParameters,
     IN  DWORD Flags,
-    OUT DWORD* PrivateHandle)
+    OUT DWORD_PTR* PrivateHandle)
 {
     MMRESULT Result;
 
@@ -170,8 +170,8 @@ MmeOpenWaveDevice(
         return TranslateInternalMmResult(Result);
     }
 
-    /* Store the device instance pointer in the private handle - is DWORD safe here? */
-    *PrivateHandle = (DWORD) SoundDeviceInstance;
+    /* Store the device instance pointer in the private handle */
+    *PrivateHandle = (DWORD_PTR)SoundDeviceInstance;
 
     /* Store the additional information we were given - FIXME: Need flags! */
     SetSoundDeviceInstanceMmeData(SoundDeviceInstance,
@@ -195,7 +195,7 @@ MmeOpenWaveDevice(
 
 MMRESULT
 MmeCloseDevice(
-    IN  DWORD PrivateHandle)
+    IN  DWORD_PTR PrivateHandle)
 {
     MMRESULT Result;
     PSOUND_DEVICE_INSTANCE SoundDeviceInstance;
@@ -235,7 +235,7 @@ MmeCloseDevice(
 
 MMRESULT
 MmeResetWavePlayback(
-    IN  DWORD PrivateHandle)
+    IN  DWORD_PTR PrivateHandle)
 {
     PSOUND_DEVICE_INSTANCE SoundDeviceInstance;
 
@@ -284,7 +284,7 @@ MMRESULT
 MmeGetPosition(
     IN  MMDEVICE_TYPE DeviceType,
     IN  DWORD DeviceId,
-    IN  DWORD PrivateHandle,
+    IN  DWORD_PTR PrivateHandle,
     IN  MMTIME* Time,
     IN  DWORD Size)
 {
diff --git a/reactos/lib/drivers/sound/mmebuddy/wave/header.c b/reactos/lib/drivers/sound/mmebuddy/wave/header.c
index bf5b80b6496..b4d7fdcf119 100644
--- a/reactos/lib/drivers/sound/mmebuddy/wave/header.c
+++ b/reactos/lib/drivers/sound/mmebuddy/wave/header.c
@@ -359,5 +359,5 @@ CompleteWaveHeader(
     /* Safe to do this without thread protection, as we're done with the header */
     NotifyMmeClient(SoundDeviceInstance,
                     DeviceType == WAVE_OUT_DEVICE_TYPE ? WOM_DONE : WIM_DATA,
-                    (DWORD) Header);
+                    (DWORD_PTR)Header);
 }
diff --git a/reactos/lib/drivers/sound/mmebuddy/wave/widMessage.c b/reactos/lib/drivers/sound/mmebuddy/wave/widMessage.c
index ce1e4dffce3..47825aeccd9 100644
--- a/reactos/lib/drivers/sound/mmebuddy/wave/widMessage.c
+++ b/reactos/lib/drivers/sound/mmebuddy/wave/widMessage.c
@@ -25,11 +25,11 @@
 DWORD
 APIENTRY
 widMessage(
-    DWORD DeviceId,
-    DWORD Message,
-    DWORD PrivateHandle,
-    DWORD Parameter1,
-    DWORD Parameter2)
+    UINT DeviceId,
+    UINT Message,
+    DWORD_PTR PrivateHandle,
+    DWORD_PTR Parameter1,
+    DWORD_PTR Parameter2)
 {
     MMRESULT Result = MMSYSERR_NOTSUPPORTED;
 
@@ -72,7 +72,7 @@ widMessage(
                                        DeviceId,
                                        (LPWAVEOPENDESC) Parameter1,
                                        Parameter2,
-                                       (DWORD*) PrivateHandle);
+                                       (DWORD_PTR*) PrivateHandle);
             break;
         }
 
diff --git a/reactos/lib/drivers/sound/mmebuddy/wave/wodMessage.c b/reactos/lib/drivers/sound/mmebuddy/wave/wodMessage.c
index de579f32200..70bd6b70d05 100644
--- a/reactos/lib/drivers/sound/mmebuddy/wave/wodMessage.c
+++ b/reactos/lib/drivers/sound/mmebuddy/wave/wodMessage.c
@@ -34,11 +34,11 @@ MMRESULT HelloWorld(PSOUND_DEVICE_INSTANCE Instance, PVOID String)
 DWORD
 APIENTRY
 wodMessage(
-    DWORD DeviceId,
-    DWORD Message,
-    DWORD PrivateHandle,
-    DWORD Parameter1,
-    DWORD Parameter2)
+    UINT DeviceId,
+    UINT Message,
+    DWORD_PTR PrivateHandle,
+    DWORD_PTR Parameter1,
+    DWORD_PTR Parameter2)
 {
     MMRESULT Result = MMSYSERR_NOTSUPPORTED;
 
@@ -69,7 +69,7 @@ wodMessage(
                                        DeviceId,
                                        (LPWAVEOPENDESC) Parameter1,
                                        Parameter2,
-                                       (DWORD*) PrivateHandle);
+                                       (DWORD_PTR*)PrivateHandle);
             break;
         }