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I am trying to copy a large folder (my music) from my Windows 7 machine to a Windows 8 machine via a LAN. Inevitably, once robocopy is run, the state of the network will start fluctuating between connected and disconnecting for the W7 machine. The disconnects happen every 20-40s without an apparent pattern and the network reconnects immediately.


Here is my robocopy command line:

robocopy "D:\copyfrom" "\\W8\Share\copyto" *.* /Z /MIR /mt /R:100 /W:30 /XF *.ini

My D drive is an external hard drive, but I have the same problem when copying from my internal drive as well.

The W7 machine is connected via ethernet and the W8 machine is connected via wifi.


I have tried adding a /TBD to the command line, but with no particular effect except that it may increase the delays between disconnects slightly.

I have tried disabling Remote Differential Compression and Auto-tuning (this helped once when trying to improve network copy speeds), but have re-enabled them as this has no effect.

EDIT: The problem was solved by changing the connection to a different port on the switch.

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Which router are you using?

Some routers will drop packets and some heavy use (such as large file transfers) situations reset their interface when under prolonged heavy data transfers. Specifically transfers that occur eth <-> wifi.

Can you clarify if it is the wifi connection that is dropping or the ethernet connection or both?

Check for interface errors and the router uptime.

How long does the network show as "disconnected"?

Also, as there is obviously some kind of network overload issue from the large file transfer, I would recommend reducing the speed of the copy proccess. This is done with the /IPG:x option in ROBOCOPY.

The following article has a good write up explaining the use of it.

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I am connected to a trendnet 8-port gigabit switch which is connected to medialink wireless-n router which connects to the W8 machine via wifi. I suspect that it's my computer that's having problems, as another person on my network connected to the switch retains internet connection when I lose my network connection (so it's either my computer or a port on my switch). The router uptime is about 2 days, whereas my last drop was about 10 minutes ago (the files finally finished copying). The network is disconnected for maybe a second or two. – William Everett Jul 11 '13 at 14:29
sorry, you still haven't clarified if it was the ethernet computer that lost connection or the wifi computer which lost connection? I'm guessing it was the wifi, as you've said your friend thats connected through the switch that continues to work. – jammin Jul 15 '13 at 2:18
Also, I've added information to the use of robocopy. You can use the /IPG option to redece the speed of the transfer and workaround the network issue. – jammin Jul 15 '13 at 2:28
I specified in the original post that the W7 machine was connected via ethernet. The problem turned out to be a bad connection at the switch as moving to another port fixed the problem. – William Everett Jul 26 '13 at 16:03

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