I was upgrading the IOS for the Cisco 6509s. I got Cisco TFTP Server setup and connected to it to download the file. The file was around 80Mb. TFTP Server threw an exception and shutdown. Upon restart, the file started to get downloaded but a few seconds later Cisco TFTP Server threw another error. This time I was able to view the error message and it said the transfer failed due to Synchronization Error.
I switched to SolarWinds TFTP Server and got a more detailed error saying the file was too large to be transferred through TFTP.
As an alternative, I used FTP Server from 3CDaemon and issued the command:
copy FTP: Disk0:
and it worked like a champ.
I had IIS running on my laptop so I turned off 3CDaemon and used IIS's FTP server. It worked out just fine.
So if you are transferring a large file you should use FTP and not TFTP to avoid potential problems and I also recommend 3CDaemon as it's got TFTP Server, FTP Server, Syslog as well as TFTP client all in one package.