diff --git a/dlls/winecoreaudio.drv/midi.c b/dlls/winecoreaudio.drv/midi.c
index e9dd93ebdd7..98d7d8fcba4 100644
--- a/dlls/winecoreaudio.drv/midi.c
+++ b/dlls/winecoreaudio.drv/midi.c
@@ -696,6 +696,52 @@ static DWORD MIDIIn_AddBuffer(WORD wDevID, LPMIDIHDR lpMidiHdr, DWORD dwSize)
     return MMSYSERR_NOERROR;
 }
 
+static DWORD MIDIIn_Prepare(WORD wDevID, LPMIDIHDR lpMidiHdr, DWORD dwSize)
+{
+    TRACE("wDevID=%d lpMidiHdr=%p dwSize=%d\n", wDevID, lpMidiHdr, dwSize);
+
+    if (wDevID >= MIDIIn_NumDevs) {
+        WARN("bad device ID : %d\n", wDevID);
+	return MMSYSERR_BADDEVICEID;
+    }
+    /* MS doc says that dwFlags must be set to zero, but (kinda funny) MS mciseq drivers
+     * asks to prepare MIDIHDR which dwFlags != 0.
+     * So at least check for the inqueue flag
+     */
+    if (dwSize < sizeof(MIDIHDR) || lpMidiHdr == 0 ||
+	lpMidiHdr->lpData == 0 || (lpMidiHdr->dwFlags & MHDR_INQUEUE) != 0 ||
+	lpMidiHdr->dwBufferLength >= 0x10000ul) {
+	WARN("Invalid parameter %p %p %08x %d/%d\n", lpMidiHdr, lpMidiHdr->lpData,
+	           lpMidiHdr->dwFlags, sizeof(MIDIHDR), dwSize);
+	return MMSYSERR_INVALPARAM;
+    }
+
+    lpMidiHdr->lpNext = 0;
+    lpMidiHdr->dwFlags |= MHDR_PREPARED;
+    lpMidiHdr->dwFlags &= ~MHDR_DONE;
+    return MMSYSERR_NOERROR;
+}
+
+static DWORD MIDIIn_Unprepare(WORD wDevID, LPMIDIHDR lpMidiHdr, DWORD dwSize)
+{
+    TRACE("wDevID=%d lpMidiHdr=%p dwSize=%d\n", wDevID, lpMidiHdr, dwSize);
+    if (wDevID >= MIDIIn_NumDevs) {
+        WARN("bad device ID : %d\n", wDevID);
+	return MMSYSERR_BADDEVICEID;
+    }
+    if (dwSize < sizeof(MIDIHDR) || lpMidiHdr == 0) {
+	WARN("Invalid Parameter\n");
+	return MMSYSERR_INVALPARAM;
+    }
+    if (lpMidiHdr->dwFlags & MHDR_INQUEUE) {
+	WARN("Still playing\n");
+	return MIDIERR_STILLPLAYING;
+    }
+
+    lpMidiHdr->dwFlags &= ~MHDR_PREPARED;
+    return MMSYSERR_NOERROR;
+}
+
 static DWORD MIDIIn_GetDevCaps(WORD wDevID, LPMIDIINCAPSW lpCaps, DWORD dwSize)
 {
     TRACE("wDevID=%d lpCaps=%p dwSize=%d\n", wDevID, lpCaps, dwSize);
@@ -897,10 +943,9 @@ DWORD WINAPI CoreAudio_midMessage(UINT wDevID, UINT wMsg, DWORD dwUser, DWORD dw
         case MIDM_ADDBUFFER:
             return MIDIIn_AddBuffer(wDevID, (LPMIDIHDR)dwParam1, dwParam2);
         case MIDM_PREPARE:
+            return MIDIIn_Prepare(wDevID, (LPMIDIHDR)dwParam1, dwParam2);
         case MIDM_UNPREPARE:
-            TRACE("Unsupported message\n");
-            return MMSYSERR_NOTSUPPORTED;
-
+            return MIDIIn_Unprepare(wDevID, (LPMIDIHDR)dwParam1, dwParam2);
         case MIDM_GETDEVCAPS:
             return MIDIIn_GetDevCaps(wDevID, (LPMIDIINCAPSW) dwParam1, dwParam2);
         case MIDM_GETNUMDEVS: