Here how to use my IPC : Client (need to be compiled): #include <Constants.au3> #include <GUIConstants.au3> #include "WCD_IPC.au3" Opt ("MustDeclareVars", 1) Local $iClientNumber = $cmdLine[1] ; $_WCD_Verbose = True Global $hWnd = _WCD_CreateClient ("Test WCD Client " & $iClientNumber) Global $hWndServer = _WCD_GetServerHandle () _WCD_Send($hWnd, $hWndServer, 1, '[Client' & $iClientNumber &