Here's the details about my computer: Windows Server 2008 Standard running 6.0.6001.18000 (Build 6001 SP 1; RAM is 4 GB; 64-bit TFTP software: Tftpd32 Service Edition copyrighted 2007-2009 by Philippe Jounin; version v3.35 When I try to download a file via TFTP from the TFTP software running on the server, I get a "Header checksum" error. Works fine on other Windows platforms tested (XP, Windows 2003/64-bit, Windows 2003/32-bit). The TFTP client sends the TFTP write request and waiting for the acknowlegement. Apparently, the client never receives any TFTP acknowledgement from the Server. Capturing packets on the TFTP server (windows 2008 server) reveals that the acknowlegements are sent but with bad IP checksum and hence the packets are not processed by the client .

Hi Bala, i'm having the same exact problem. Have you found a solution?