I have a Windows 7 Pro 64bit computer with a mapped drive to our server on the internet. I can successfully logon and transfer small files, however the large files eventually fail and pop up a message box say "There is a problem accessing Z:\. Make sure you are connected to the network and try again", clicking the Try Again button doesn't recover the transfer. I once got this error 0x80070057: The parameter is incorrect but usually I just get the message box mentioned before. I have tried doing a transfer with my anti-virus turned off, with no success. I have downloaded Network Monitor 3.4 to try and find what is causing the issue but every transfer I do with Network Monitor running, completes. The transfer to the server does work on my Windows XP Pro computer but if I run a virtual machine on the Windows 7 computer then the transfer fails. Any suggestions would be greatly appreciated.