Fix Problems with Copying Large Files in Windows Vista

Possibly you have previously encountered the strange behaviour that it takes much longer to copy large files in Windows Vista than in Windows XP. You thinking that the change from XP to Vista would at least be not a bother speed wise but Vista in some way seems to have a problem copying large files. This happens particularly with mapped drives but it could also be that you witness network disconnects.

Trouble is caused by a new feature called Auto Tuning which is by default enabled in Microsoft Windows Vista. What Auto Tuning does is that it reacts on changes in the network by tuning the receive windows size. The solution would be of course to hinder Auto Tuning in Vista. Some users reported that disabling Auto Tuning had a positive effect on their ability to connect to services such as Windows Live Messenger which did not work before.

Though Windows Vista is a major improvement over Windows XP, there is one particular virus that has really upset me which is how slowly it moves or deletes files. In Windows XP there were no problems moving big files. However, with Windows Vista if you move big files even on the same drive there is a long pause while it calculates how long it will take and the actual move takes forever, but on XP it is instantaneous.

So if you have been having problems copying large files over network disconnects, mapped drives, , or having to reboot your router a lot more frequently than normal, in that case you can try out this fix to solve the problem.

The difficulty stems from the new auto-tuning network, which changes the receive window on the fly. Thankfully we can easily turn it off from an administrative mode command prompt.

Open Administrative Mode Command Prompt:

Either type cmd into the start menu and use Ctrl+Shift+Enter or right-click the Command Prompt shortcut and choose Run as Administrator.
Now turn off auto tuning.

netsh int tcp set global autotuninglevel=disabled

You will have to restart your system, but one time you do, the problems should be resolute. If they are not you can always turn auto-tuning back on.
Now turn On Auto-Tuning.

netsh int tcp set global autotuninglevel=normal

After that problem will be resolved.