diff --git a/asyncdispatch2/transports/common.nim b/asyncdispatch2/transports/common.nim
index 2bb846c..a740e20 100644
--- a/asyncdispatch2/transports/common.nim
+++ b/asyncdispatch2/transports/common.nim
@@ -113,5 +113,6 @@ when defined(windows):
   import winlean
 
   const ERROR_OPERATION_ABORTED* = 995
+  const ERROR_SUCCESS* = 0
   proc cancelIo*(hFile: HANDLE): WINBOOL
        {.stdcall, dynlib: "kernel32", importc: "CancelIo".}
diff --git a/asyncdispatch2/transports/datagram.nim b/asyncdispatch2/transports/datagram.nim
index c730c54..3ed4f92 100644
--- a/asyncdispatch2/transports/datagram.nim
+++ b/asyncdispatch2/transports/datagram.nim
@@ -7,7 +7,7 @@
 #  Apache License, version 2.0, (LICENSE-APACHEv2)
 #              MIT license (LICENSE-MIT)
 
-import net, nativesockets, os, deques
+import net, nativesockets, os, deques, strutils
 import ../asyncloop, ../handles
 import common
 
@@ -20,7 +20,7 @@ when defined(windows):
   type
     GramVector = object
       kind: VectorKind            # Vector kind (with address/without address)
-      buf: TWSABuf                # Writer vector buffer
+      buf: ptr TWSABuf            # Writer vector buffer
       address: TransportAddress   # Destination address
       writer: Future[void]        # Writer vector completion Future
 
@@ -91,6 +91,7 @@ when defined(windows):
       return
     var ovl = cast[PCustomOverlapped](udata)
     var transp = cast[WindowsDatagramTransport](ovl.data.udata)
+    echo "writeDatagramLoop(" & toHex(cast[uint](transp)) & ")"
     while len(transp.queue) > 0:
       if WritePending in transp.state:
         ## Continuation
@@ -108,12 +109,12 @@ when defined(windows):
         var slen: SockLen
         transp.state.incl(WritePending)
         let fd = SocketHandle(ovl.data.fd)
-        var vector = transp.queue[0]
+        var vector = transp.queue.popFirst()
         if vector.kind == WithAddress:
           toSockAddr(vector.address.address, vector.address.port, saddr, slen)
         else:
           toSockAddr(transp.remote.address, transp.remote.port, saddr, slen)
-        let ret = WSASendTo(fd, addr vector.buf, DWORD(1), addr bytesCount,
+        let ret = WSASendTo(fd, vector.buf, DWORD(1), addr bytesCount,
                             DWORD(0), cast[ptr SockAddr](addr saddr),
                             cint(slen),
                             cast[POVERLAPPED](addr transp.wovl), nil)
@@ -121,10 +122,14 @@ when defined(windows):
           let err = osLastError()
           if int(err) == ERROR_OPERATION_ABORTED:
             transp.state.incl(WritePaused)
-          elif int(err) != ERROR_IO_PENDING:
+          elif int(err) == ERROR_IO_PENDING:
+            transp.queue.addFirst(vector)
+          else:
             transp.state.excl(WritePending)
             transp.setWriteError(err)
             transp.finishWriter()
+        else:
+          transp.queue.addFirst(vector)
         break
 
     if len(transp.queue) == 0:
@@ -257,8 +262,6 @@ when defined(windows):
     if remote.port != Port(0):
       wresult.remote = remote
 
-    ## TODO: Apply server flags
-
     wresult.fd = localSock
     wresult.function = cbproc
     wresult.buffer = newSeq[byte](bufferSize)
@@ -464,8 +467,8 @@ proc send*(transp: DatagramTransport, pbytes: pointer,
     raise newException(TransportError, "Remote peer is not set!")
   var waitFuture = newFuture[void]("datagram.transport.send")
   when defined(windows):
-    let wsabuf = TWSABuf(buf: cast[cstring](pbytes), len: int32(nbytes))
-    var vector = GramVector(kind: WithoutAddress, buf: wsabuf,
+    var wsabuf = TWSABuf(buf: cast[cstring](pbytes), len: int32(nbytes))
+    var vector = GramVector(kind: WithoutAddress, buf: addr wsabuf,
                             writer: waitFuture)
   else:
     var vector = GramVector(kind: WithoutAddress, buf: pbytes, buflen: nbytes,
@@ -482,15 +485,16 @@ proc sendTo*(transp: DatagramTransport, pbytes: pointer, nbytes: int,
   checkClosed(transp)
   var saddr: Sockaddr_storage
   var slen: SockLen
+  var vector: GramVector
   toSockAddr(remote.address, remote.port, saddr, slen)
   var waitFuture = newFuture[void]("datagram.transport.sendto")
   when defined(windows):
-    let wsabuf = TWSABuf(buf: cast[cstring](pbytes), len: int32(nbytes))
-    var vector = GramVector(kind: WithAddress, buf: wsabuf,
-                            address: remote, writer: waitFuture)
+    var wsabuf = TWSABuf(buf: cast[cstring](pbytes), len: int32(nbytes))
+    vector = GramVector(kind: WithAddress, buf: addr wsabuf,
+                        address: remote, writer: waitFuture)
   else:
-    var vector = GramVector(kind: WithAddress, buf: pbytes, buflen: nbytes,
-                            address: remote, writer: waitFuture)
+    vector = GramVector(kind: WithAddress, buf: pbytes, buflen: nbytes,
+                        address: remote, writer: waitFuture)
   transp.queue.addLast(vector)
   if WritePaused in transp.state:
     transp.resumeWrite()
diff --git a/tests/testdatagram.nim b/tests/testdatagram.nim
index a2ba657..f709678 100644
--- a/tests/testdatagram.nim
+++ b/tests/testdatagram.nim
@@ -3,8 +3,11 @@ import ../asyncdispatch2
 
 const
   TestsCount = 5000
-  ClientsCount = 10
-  MessagesCount = 50
+  ClientsCount = 2
+  MessagesCount = 350
+
+when defined(vcc):
+  {.passC: "/Zi /FS".}
 
 proc client1(transp: DatagramTransport, pbytes: pointer, nbytes: int,
              raddr: TransportAddress, udata: pointer): Future[void] {.async.} =
@@ -92,6 +95,7 @@ proc client4(transp: DatagramTransport, pbytes: pointer, nbytes: int,
         transp.close()
       else:
         var req = "REQUEST" & $counterPtr[]
+        echo $counterPtr[] & "-SEND"
         await transp.send(addr req[0], len(req))
     else:
       echo "ERROR"
@@ -153,8 +157,9 @@ proc test3(): Future[int] {.async.} =
   for i in 0..<ClientsCount:
     var dgram = newDatagramTransport(client4, udata = addr counters[i],
                                      remote = ta)
+    echo "FIRST SEND at " & toHex(cast[uint](dgram))
     var data = "REQUEST0"
-    await dgram.send(addr data[0], len(data))
+    await dgram.sendTo(addr data[0], len(data), ta)
     clients[i] = dgram.join()
 
   await waitAll(clients)