diff --git a/windows/winmme/JackWinMMEInputPort.cpp b/windows/winmme/JackWinMMEInputPort.cpp
index 856375ff..2c0b43b5 100644
--- a/windows/winmme/JackWinMMEInputPort.cpp
+++ b/windows/winmme/JackWinMMEInputPort.cpp
@@ -64,11 +64,8 @@ JackWinMMEInputPort::JackWinMMEInputPort(const char *alias_name,
         goto delete_sysex_buffer;
     }
     sysex_header.dwBufferLength = max_bytes;
-    sysex_header.dwBytesRecorded = 0;
     sysex_header.dwFlags = 0;
-    sysex_header.dwUser = 0;
     sysex_header.lpData = (LPSTR)(((LPBYTE) &sysex_header) + sizeof(MIDIHDR));
-    sysex_header.lpNext = 0;
     result = midiInPrepareHeader(handle, &sysex_header, sizeof(MIDIHDR));
     if (result != MMSYSERR_NOERROR) {
         GetInErrorString(result, error_message);
@@ -104,7 +101,7 @@ JackWinMMEInputPort::JackWinMMEInputPort(const char *alias_name,
     result = midiInUnprepareHeader(handle, &sysex_header, sizeof(MIDIHDR));
     if (result != MMSYSERR_NOERROR) {
         WriteInError("JackWinMMEInputPort [constructor]",
-                   "midiInUnprepareHeader", result);
+                     "midiInUnprepareHeader", result);
     }
  close_handle:
     result = midiInClose(handle);
diff --git a/windows/winmme/JackWinMMEOutputPort.cpp b/windows/winmme/JackWinMMEOutputPort.cpp
index 9a6247a5..dc1f8a70 100644
--- a/windows/winmme/JackWinMMEOutputPort.cpp
+++ b/windows/winmme/JackWinMMEOutputPort.cpp
@@ -184,11 +184,8 @@ JackWinMMEOutputPort::Execute()
         }
         MIDIHDR header;
         header.dwBufferLength = size;
-        header.dwBytesRecorded = size;
         header.dwFlags = 0;
-        header.dwOffset = 0;
-        header.dwUser = 0;
-        header.lpData = (LPSTR)data;
+        header.lpData = (LPSTR) data;
         result = midiOutPrepareHeader(handle, &header, sizeof(MIDIHDR));
         if (result != MMSYSERR_NOERROR) {
             WriteOutError("JackWinMMEOutputPort::Execute",
@@ -215,7 +212,6 @@ JackWinMMEOutputPort::Execute()
                          "midiOutUnprepareHeader", result);
             break;
         }
-
     }
     return false;
 }
@@ -236,7 +232,7 @@ JackWinMMEOutputPort::HandleMessage(UINT message, DWORD_PTR param1,
         jack_info("JackWinMMEOutputPort::HandleMessage - MIDI device opened.");
         break;
     case MOM_POSITIONCB:
-        LPMIDIHDR header = (LPMIDIHDR) param2;
+        LPMIDIHDR header = (LPMIDIHDR) param1;
         jack_info("JackWinMMEOutputPort::HandleMessage - %d bytes out of %d "
                   "bytes of the current sysex message have been sent.",
                   header->dwOffset, header->dwBytesRecorded);