diff --git a/Source/win32/GSRunLoopCtxt.m b/Source/win32/GSRunLoopCtxt.m
index 953afb70f..15cd7dc24 100644
--- a/Source/win32/GSRunLoopCtxt.m
+++ b/Source/win32/GSRunLoopCtxt.m
@@ -429,6 +429,7 @@ static const NSMapTableValueCallBacks WatcherMapValueCallBacks =
        * The watcher is still valid - so call its receivers
        * event handling method.
        */
+      NSDebugMLLog(@"NSRunLoop", @"Event callback found");
       (*watcher->handleEvent)(watcher->receiver,
           eventSel, watcher->data, watcher->type,
           (void*)(gsaddr)handle, mode);
diff --git a/Source/win32/NSMessagePortWin32.m b/Source/win32/NSMessagePortWin32.m
index ce8f4a3c8..3e7b5bed7 100644
--- a/Source/win32/NSMessagePortWin32.m
+++ b/Source/win32/NSMessagePortWin32.m
@@ -96,6 +96,13 @@ typedef struct {
   unsigned char	port[16];
 } GSPortMsgHeader;
 
+typedef enum {
+  RS_NONE,	// Not started yet
+  RS_MESG,	// Waiting to be notified of a message arriving
+  RS_SIZE,	// Need to determine message size
+  RS_DATA	// Need to read message data
+} ReadState;
+
 typedef	struct {
   NSString              *name;
   NSRecursiveLock       *lock;
@@ -103,6 +110,7 @@ typedef	struct {
   HANDLE                wHandle;
   HANDLE                rEvent;
   HANDLE                wEvent;
+  ReadState		rState;
   OVERLAPPED		rOv;
   OVERLAPPED		wOv;
   DWORD			rSize;
@@ -309,6 +317,7 @@ static unsigned	wordAlign;
   this->wHandle = INVALID_HANDLE_VALUE;
   this->wEvent = INVALID_HANDLE_VALUE;
 
+  this->rState = RS_NONE;
   this->rEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
   this->rData = [NSMutableData new];
   this->rMsgs = [NSMutableArray new];
@@ -367,6 +376,8 @@ static unsigned	wordAlign;
 
       this->lock = [GSLazyRecursiveLock new];
 
+      this->rState = RS_NONE;
+
       this->rHandle = INVALID_HANDLE_VALUE;
       this->rEvent = INVALID_HANDLE_VALUE;
       this->wHandle = INVALID_HANDLE_VALUE;
@@ -476,7 +487,9 @@ static unsigned	wordAlign;
 
   M_LOCK(this->lock);
 
-  if (this->rWant > 0)
+  NSDebugMLLog(@"NSMessagePort", @"entered with rWant=%d", this->rWant);
+
+  if (this->rState == RS_MESG)
     {
       /*
        * Have we read something?
@@ -488,6 +501,7 @@ static unsigned	wordAlign;
 	TRUE) == 0)
 	{
 	  errno = GetLastError();
+	  NSDebugMLLog(@"NSMessagePort", @"overlapped result=%d", errno);
 	  /*
 	   * Our overlapped read attempt should fail ... because mailslots
 	   * insist we read an entire message in one go, and we asked it
@@ -498,210 +512,214 @@ static unsigned	wordAlign;
 	   */
 	  if (errno == ERROR_INSUFFICIENT_BUFFER)
 	    {
-	      if (GetMailslotInfo(
-		this->rHandle,
-		0,
-		&this->rWant,
-		0,
-		0) == 0)
-		{
-		  NSLog(@"unable to get info from mailslot '%@' - %s",
-		    this->name, GSLastErrorStr(errno));
-		  [self invalidate];
-		  return;
-		}
-	      else
-		{
-		  [this->rData setLength: this->rWant];
-		  if (ReadFile(this->rHandle,
-		    [this->rData mutableBytes],	// Store results here
-		    this->rWant,
-		    &this->rSize,
-		    NULL) == 0)
-		    {
-		      NSLog(@"unable to read from mailslot '%@' - %s",
-			this->name, GSLastErrorStr(errno));
-		      [self invalidate];
-		      return;
-		    }
-		  if (this->rSize != this->rWant)
-		    {
-		      NSLog(@"only read %d of %d bytes from mailslot '%@' - %s",
-			this->rSize, this->rWant, this->name,
-			GSLastErrorStr(errno));
-		      [self invalidate];
-		      return;
-		    }
-		  else
-		    {
-		      NSDebugMLLog(@"NSMessagePort", @"Read complete on %@",
-			self);
-		    }
-		  this->rLength = this->rSize;
-		  this->rSize = 0;
-		}
+	      this->rState = RS_SIZE;
 	    }
 	  else
 	    {
 	      NSLog(@"GetOverlappedResult failed ...%s", GSLastErrorStr(errno));
+	      this->rState = RS_NONE;
 	      this->rLength = 0;
-	      this->rWant = 1;
 	    }
 	}
       else
 	{
-	  NSLog(@"GetOverlappedResult succes ...%u", this->rSize);
-	  this->rLength += this->rSize;
-	  this->rSize = 0;
-	}
-
-      /*
-       * Do next part only if we have completed a read.
-       */
-      if (this->rLength == this->rWant)
-	{
-	  unsigned char		*buf = [this->rData mutableBytes];
-	  GSPortItemType	rType;
-	  GSPortItemHeader	*pih;
-	  unsigned		off = 0;
-	  unsigned		len;
-	  unsigned		rId;
-	  unsigned		nItems;
-	  NSMessagePort		*rPort = nil;
-	  NSMutableArray	*rItems = nil;
-
-	  while (off + sizeof(GSPortItemHeader) <= this->rLength)
-	    {
-	      pih = (GSPortItemHeader*)(buf + off);
-	      off += sizeof(GSPortItemHeader);
-	      rType = GSSwapBigI32ToHost(pih->type);
-	      len = GSSwapBigI32ToHost(pih->length);
-	      if (len + off > this->rLength)
-		{
-		  NSLog(@"%@ - unreasonable length (%u) for data", self, len);
-		  break;
-		}
-	      if (rType != GSP_HEAD && rItems == nil)
-		{
-		  NSLog(@"%@ - initial part of message had bad type");
-		  break;
-		}
-
-	      if (rType == GSP_HEAD)
-		{
-		  GSPortMsgHeader	*pmh;
-		  NSString		*n;
-		  NSMutableData		*d;
-
-		  if (len < sizeof(GSPortMsgHeader))
-		    {
-		      NSLog(@"%@ - bad length for header", self);
-		      break;
-		    }
-		  pmh = (GSPortMsgHeader*)(buf + off);
-		  off += sizeof(GSPortMsgHeader);
-		  len -= sizeof(GSPortMsgHeader);
-		  rId = GSSwapBigI32ToHost(pmh->mId);
-		  nItems = GSSwapBigI32ToHost(pmh->nItems);
-		  if (nItems == 0)
-		    {
-		      NSLog(@"%@ - unable to decode item count", self);
-		      break;
-		    }
-		  n = [[NSString alloc] initWithBytes: pmh->port
-					       length: 16
-					     encoding: NSASCIIStringEncoding];
-		  NSDebugFLLog(@"NSMessagePort", @"Decoded port as '%@'", n);
-		  rPort = [messagePortClass newWithName: n];
-		  RELEASE(n);
-		  if (rPort == nil)
-		    {
-		      NSLog(@"%@ - unable to decode remote port", self);
-		      break;
-		    }
-		  rItems = [NSMutableArray alloc];
-		  rItems = [rItems initWithCapacity: nItems];
-		  d = [[NSMutableData alloc] initWithBytes: buf + off
-						    length: len];
-		  [rItems addObject: d];
-		  RELEASE(d);
-		}
-	      else if (rType == GSP_DATA)
-		{
-		  NSMutableData	*d;
-
-		  d = [[NSMutableData alloc] initWithBytes: buf + off
-						    length: len];
-		  [rItems addObject: d];
-		  RELEASE(d);
-		}
-	      else if (rType == GSP_PORT)
-		{
-		  NSMessagePort	*p;
-		  NSString	*n;
-
-		  if (len != 16)
-		    {
-		      NSLog(@"%@ - bad length for port item", self);
-		      break;
-		    }
-		  n = [[NSString alloc] initWithBytes: buf + off
-					       length: 16
-					     encoding: NSASCIIStringEncoding];
-		  NSDebugFLLog(@"NSMessagePort", @"Decoded port as '%@'", n);
-		  p = [messagePortClass newWithName: n];
-		  RELEASE(n);
-		  if (p == nil)
-		    {
-		      NSLog(@"%@ - unable to decode remote port", self);
-		      break;
-		    }
-		  [rItems addObject: p];
-		  RELEASE(p);
-		}
-	      off += len;
-	      if (nItems == [rItems count])
-		{
-		  NSPortMessage	*pm;
-
-		  pm = [NSPortMessage allocWithZone: NSDefaultMallocZone()];
-		  pm = [pm initWithSendPort: rPort
-				receivePort: self
-				 components: rItems];
-		  DESTROY(rPort);
-		  DESTROY(rItems);
-		  [pm setMsgid: rId];
-		  [this->rMsgs addObject: pm];
-		  RELEASE(pm);
-		  break;
-		}
-	    }
-	  DESTROY(rPort);
-	  DESTROY(rItems);
-	  this->rWant = 1;		// Queue a read
+	  NSLog(@"GetOverlappedResult success ...%u", this->rSize);
+	  this->rState = RS_NONE;
 	  this->rLength = 0;
 	}
+    }
+
+  if (this->rState == RS_SIZE)
+    {
+      if (GetMailslotInfo(
+	this->rHandle,
+	0,
+	&this->rWant,
+	0,
+	0) == 0)
+	{
+	  NSLog(@"unable to get info from mailslot '%@' - %s",
+	    this->name, GSLastErrorStr(errno));
+	  [self invalidate];
+	  return;
+	}
       else
 	{
-	  NSLog(@"Unexpected STATE");
+	  this->rState = RS_DATA;
+	  NSDebugMLLog(@"NSMessagePort", @"mailslot size=%d",
+	    this->rWant);
+	  [this->rData setLength: this->rWant];
+	  if (ReadFile(this->rHandle,
+	    [this->rData mutableBytes],	// Store results here
+	    this->rWant,
+	    &this->rSize,
+	    NULL) == 0)
+	    {
+	      NSLog(@"unable to read from mailslot '%@' - %s",
+		this->name, GSLastErrorStr(errno));
+	      [self invalidate];
+	      return;
+	    }
+	  if (this->rSize != this->rWant)
+	    {
+	      NSLog(@"only read %d of %d bytes from mailslot '%@' - %s",
+		this->rSize, this->rWant, this->name,
+		GSLastErrorStr(errno));
+	      [self invalidate];
+	      return;
+	    }
+	  else
+	    {
+	      NSDebugMLLog(@"NSMessagePort", @"Read complete on %@",
+		self);
+	    }
+	  this->rLength = this->rSize;
+	  this->rSize = 0;
+	  this->rState = RS_NONE;
 	}
     }
-  else
+
+  /*
+   * Do next part only if we have completed a read.
+   */
+  if (this->rLength > 0 && this->rLength == this->rWant)
     {
-      this->rWant = 1;		// Queue a read
-      this->rLength = 0;
+      unsigned char	*buf = [this->rData mutableBytes];
+      GSPortItemType	rType;
+      GSPortItemHeader	*pih;
+      unsigned		off = 0;
+      unsigned		len;
+      unsigned		rId;
+      unsigned		nItems;
+      NSMessagePort	*rPort = nil;
+      NSMutableArray	*rItems = nil;
+
+      while (off + sizeof(GSPortItemHeader) <= this->rLength)
+	{
+	  pih = (GSPortItemHeader*)(buf + off);
+	  off += sizeof(GSPortItemHeader);
+	  rType = GSSwapBigI32ToHost(pih->type);
+	  len = GSSwapBigI32ToHost(pih->length);
+	  if (len + off > this->rLength)
+	    {
+	      NSLog(@"%@ - unreasonable length (%u) for data", self, len);
+	      break;
+	    }
+	  if (rType != GSP_HEAD && rItems == nil)
+	    {
+	      NSLog(@"%@ - initial part of message had bad type");
+	      break;
+	    }
+
+	  if (rType == GSP_HEAD)
+	    {
+	      GSPortMsgHeader	*pmh;
+	      NSString		*n;
+	      NSMutableData		*d;
+
+	      if (len < sizeof(GSPortMsgHeader))
+		{
+		  NSLog(@"%@ - bad length for header", self);
+		  break;
+		}
+	      pmh = (GSPortMsgHeader*)(buf + off);
+	      off += sizeof(GSPortMsgHeader);
+	      len -= sizeof(GSPortMsgHeader);
+	      rId = GSSwapBigI32ToHost(pmh->mId);
+	      nItems = GSSwapBigI32ToHost(pmh->nItems);
+	      if (nItems == 0)
+		{
+		  NSLog(@"%@ - unable to decode item count", self);
+		  break;
+		}
+	      n = [[NSString alloc] initWithBytes: pmh->port
+					   length: 16
+					 encoding: NSASCIIStringEncoding];
+	      NSDebugFLLog(@"NSMessagePort", @"Decoded port as '%@'", n);
+	      rPort = [messagePortClass newWithName: n];
+	      RELEASE(n);
+	      if (rPort == nil)
+		{
+		  NSLog(@"%@ - unable to decode remote port", self);
+		  break;
+		}
+	      rItems = [NSMutableArray alloc];
+	      rItems = [rItems initWithCapacity: nItems];
+	      d = [[NSMutableData alloc] initWithBytes: buf + off
+						length: len];
+	      [rItems addObject: d];
+	      RELEASE(d);
+	    }
+	  else if (rType == GSP_DATA)
+	    {
+	      NSMutableData	*d;
+
+	      d = [[NSMutableData alloc] initWithBytes: buf + off
+						length: len];
+	      [rItems addObject: d];
+	      RELEASE(d);
+	    }
+	  else if (rType == GSP_PORT)
+	    {
+	      NSMessagePort	*p;
+	      NSString	*n;
+
+	      if (len != 16)
+		{
+		  NSLog(@"%@ - bad length for port item", self);
+		  break;
+		}
+	      n = [[NSString alloc] initWithBytes: buf + off
+					   length: 16
+					 encoding: NSASCIIStringEncoding];
+	      NSDebugFLLog(@"NSMessagePort", @"Decoded port as '%@'", n);
+	      p = [messagePortClass newWithName: n];
+	      RELEASE(n);
+	      if (p == nil)
+		{
+		  NSLog(@"%@ - unable to decode remote port", self);
+		  break;
+		}
+	      [rItems addObject: p];
+	      RELEASE(p);
+	    }
+	  off += len;
+	  if (nItems == [rItems count])
+	    {
+	      NSPortMessage	*pm;
+
+	      pm = [NSPortMessage allocWithZone: NSDefaultMallocZone()];
+	      pm = [pm initWithSendPort: rPort
+			    receivePort: self
+			     components: rItems];
+	      DESTROY(rPort);
+	      DESTROY(rItems);
+	      [pm setMsgid: rId];
+	      [this->rMsgs addObject: pm];
+	      RELEASE(pm);
+	      break;
+	    }
+	}
+      DESTROY(rPort);
+      DESTROY(rItems);
     }
 
   /*
    * Got something ... is it all we want? If not, ask to read more.
    */
-  if ([self isValid] == YES && this->rLength < this->rWant)
+  if ([self isValid] == YES
+    && (this->rState == RS_NONE || this->rLength < this->rWant))
     {
       int	rc;
 
       this->rOv.Offset = 0;
       this->rOv.OffsetHigh = 0;
       this->rOv.hEvent = this->rEvent;
+      if (this->rState == RS_NONE)
+	{
+	  this->rLength = 0;
+	  this->rWant = 1;
+	}
       if ([this->rData length] < (this->rWant - this->rLength))
 	{
 	  [this->rData setLength: this->rWant - this->rLength];
@@ -715,15 +733,27 @@ static unsigned	wordAlign;
       if (rc > 0)
 	{
 	  NSDebugMLLog(@"NSMessagePort", @"Read immediate on %@", self);
+	  if (this->rState == RS_NONE)
+	    {
+	      this->rState = RS_SIZE;
+	    }
 	  SetEvent(this->rEvent);
 	}
       else if ((errno = GetLastError()) == ERROR_IO_PENDING)
 	{
 	  NSDebugMLLog(@"NSMessagePort", @"Read queued on %@", self);
+	  if (this->rState == RS_NONE)
+	    {
+	      this->rState = RS_MESG;
+	    }
 	}
       else if (errno == ERROR_INSUFFICIENT_BUFFER)
 	{
 	  NSDebugMLLog(@"NSMessagePort", @"Read retry on %@", self);
+	  if (this->rState == RS_NONE)
+	    {
+	      this->rState = RS_SIZE;
+	    }
 	  SetEvent(this->rEvent);
 	}
       else
@@ -792,6 +822,8 @@ static unsigned	wordAlign;
 	}
     }
 
+again:
+
   /*
    * Handle start of next data item if we have completed one,
    * or if we are called without a write in progress.
@@ -828,7 +860,8 @@ static unsigned	wordAlign;
 	{
 	  NSDebugMLLog(@"NSMessagePort", @"Write of %d performs %d",
 	    [this->wData length] - this->wLength, this->wSize);
-	  SetEvent(this->wEvent);
+	  this->wLength += this->wSize;
+	  goto again;
 	}
       else if ((errno = GetLastError()) != ERROR_IO_PENDING)
 	{
@@ -855,6 +888,7 @@ static unsigned	wordAlign;
     {
       internal	*this = PORT(self);
 
+      NSDebugMLLog(@"NSMessagePort", @"got event on %@ in mode %@", self, mode);
       if (this->rEvent == (HANDLE)data)
 	{
 	  [self receivedEventRead];
@@ -866,7 +900,8 @@ static unsigned	wordAlign;
     }
   else
     {
-      // Event on invalid port ... remove port from run loop
+      NSDebugMLLog(@"NSMessagePort",
+	@"got event on invalidated port 0x%x in mode %@", self, mode);
       [[NSRunLoop currentRunLoop] removeEvent: data
 					 type: type
 				      forMode: mode