to write information on the processing state to the GUI inside a tcpserver.onexecute(..) function , i used the following command sequence ExecuteDUMMYCommand(Global_Send_Record); BitMap_PaintImageProcess; TThread.Synchronize(nil, BitMap_PaintImageProcess); The code is working well on some machines, but on a few it fails. The code execution stops atTThread.Synchronize command. I guess on these machines the function call is trapped inside a deadlock Any chance to figure out the real problem behind ? The procedure BitMap_PaintImageProcess , here I create a Bitmap and do a lot of painting stuff , but is seems that this code is never executed ?