diff --git a/dlls/winecoreaudio.drv/midi.c b/dlls/winecoreaudio.drv/midi.c
index b6b26ea2ab5..bb105fcb720 100644
--- a/dlls/winecoreaudio.drv/midi.c
+++ b/dlls/winecoreaudio.drv/midi.c
@@ -222,7 +222,7 @@ LONG CoreAudio_MIDIRelease(void)
 /**************************************************************************
  * 			MIDI_NotifyClient			[internal]
  */
-static DWORD MIDI_NotifyClient(UINT wDevID, WORD wMsg, DWORD dwParam1, DWORD dwParam2)
+static void MIDI_NotifyClient(UINT wDevID, WORD wMsg, DWORD dwParam1, DWORD dwParam2)
 {
     DWORD 		dwCallBack;
     UINT 		uFlags;
@@ -255,12 +255,11 @@ static DWORD MIDI_NotifyClient(UINT wDevID, WORD wMsg, DWORD dwParam1, DWORD dwP
 	dwInstance = sources[wDevID].midiDesc.dwInstance;
         break;
     default:
-	WARN("Unsupported MSW-MIDI message %u\n", wMsg);
-	return MMSYSERR_ERROR;
+	ERR("Unsupported MSW-MIDI message %u\n", wMsg);
+	return;
     }
 
-    return DriverCallback(dwCallBack, uFlags, hDev, wMsg, dwInstance, dwParam1, dwParam2) ?
-        MMSYSERR_NOERROR : MMSYSERR_ERROR;
+    DriverCallback(dwCallBack, uFlags, hDev, wMsg, dwInstance, dwParam1, dwParam2);
 }
 
 static DWORD MIDIOut_Open(WORD wDevID, LPMIDIOPENDESC lpDesc, DWORD dwFlags)
@@ -307,7 +306,8 @@ static DWORD MIDIOut_Open(WORD wDevID, LPMIDIOPENDESC lpDesc, DWORD dwFlags)
     dest->wFlags = HIWORD(dwFlags & CALLBACK_TYPEMASK);
     dest->midiDesc = *lpDesc;
 
-    return MIDI_NotifyClient(wDevID, MOM_OPEN, 0L, 0L);
+    MIDI_NotifyClient(wDevID, MOM_OPEN, 0L, 0L);
+    return MMSYSERR_NOERROR;
 }
 
 static DWORD MIDIOut_Close(WORD wDevID)
@@ -327,10 +327,7 @@ static DWORD MIDIOut_Close(WORD wDevID)
     destinations[wDevID].graph = 0;
     destinations[wDevID].synth = 0;
 
-    if (MIDI_NotifyClient(wDevID, MOM_CLOSE, 0L, 0L) != MMSYSERR_NOERROR) {
-	WARN("can't notify client !\n");
-	ret = MMSYSERR_INVALPARAM;
-    }
+    MIDI_NotifyClient(wDevID, MOM_CLOSE, 0L, 0L);
     destinations[wDevID].midiDesc.hMidi = 0;
 
     return ret;
@@ -446,10 +443,7 @@ static DWORD MIDIOut_LongData(WORD wDevID, LPMIDIHDR lpMidiHdr, DWORD dwSize)
 
     lpMidiHdr->dwFlags &= ~MHDR_INQUEUE;
     lpMidiHdr->dwFlags |= MHDR_DONE;
-    if (MIDI_NotifyClient(wDevID, MOM_DONE, (DWORD)lpMidiHdr, 0L) != MMSYSERR_NOERROR) {
-	WARN("can't notify client !\n");
-	return MMSYSERR_INVALPARAM;
-    }
+    MIDI_NotifyClient(wDevID, MOM_DONE, (DWORD)lpMidiHdr, 0L);
     return MMSYSERR_NOERROR;
 }
 
@@ -632,7 +626,8 @@ static DWORD MIDIIn_Open(WORD wDevID, LPMIDIOPENDESC lpDesc, DWORD dwFlags)
     sources[wDevID].startTime = 0;
     sources[wDevID].state = 0;
 
-    return MIDI_NotifyClient(wDevID, MIM_OPEN, 0L, 0L);
+    MIDI_NotifyClient(wDevID, MIM_OPEN, 0L, 0L);
+    return MMSYSERR_NOERROR;
 }
 
 static DWORD MIDIIn_Close(WORD wDevID)
@@ -654,7 +649,7 @@ static DWORD MIDIIn_Close(WORD wDevID)
 	return MIDIERR_STILLPLAYING;
     }
 
-    ret = MIDI_NotifyClient(wDevID, MIM_CLOSE, 0L, 0L);
+    MIDI_NotifyClient(wDevID, MIM_CLOSE, 0L, 0L);
     sources[wDevID].midiDesc.hMidi = 0;
     return ret;
 }
@@ -814,9 +809,7 @@ static DWORD MIDIIn_Reset(WORD wDevID)
 	sources[wDevID].lpQueueHdr->dwFlags &= ~MHDR_INQUEUE;
 	sources[wDevID].lpQueueHdr->dwFlags |= MHDR_DONE;
 	/* FIXME: when called from 16 bit, lpQueueHdr needs to be a segmented ptr */
-	if (MIDI_NotifyClient(wDevID, MIM_LONGDATA, (DWORD)sources[wDevID].lpQueueHdr, dwTime) != MMSYSERR_NOERROR) {
-	    WARN("Couldn't notify client\n");
-	}
+	MIDI_NotifyClient(wDevID, MIM_LONGDATA, (DWORD)sources[wDevID].lpQueueHdr, dwTime);
 	sources[wDevID].lpQueueHdr = (LPMIDIHDR)sources[wDevID].lpQueueHdr->lpNext;
     }
     LeaveCriticalSection(&midiInLock);