I have been using Windows Vista for quite some time now - occasionally since Beta 2, and full-time since RC1. One thing that has become an increasing irritation is that copying files seems to sometimes take forever. This is particularly true when working with files on a network drive. The dialog box just sits there saying Calculating for an insane amount of time and then finally starts working. It was driving me nuts. After doing some research, I found a few possible solutions.
Disable Remote Differential Compression. This is a feature that supposedly compares two files and transfers the difference. In theory, this should save bandwidth and disk I/O. In my experience, it is terrible. I can only assume that when copying large amounts of data, it takes it a long time to calculate what needs to be transferred. Once I disabled this feature, things sped up dramatically for me. In fact, I did not attempt any of the other options. I am satisfied at this point. 
To disable Remote Differential Compression, go to Control Panel - Program and Features and select Turn Windows Features On or Off on the left side. Uncheck the selection for Remote Differential Compression. If this does not clear up the problem for you, keep reading.
If you are using a Linksys or other off-the-shelf router, network auto-tuning might be the problem. Auto-tuning is a capability of the Vista TCP/IP stack that allows it to adjust to various network conditions to achieve better performance. Unfortunately, if your network hardware does not play well with it, the feature can really bog things down. If this is the case for you, go to a command prompt and disable auto-tuning with the following commands:
netsh interface tcp set global autotuning level=disabled
netsh interface tcp set global rss=disabled
If you want to re-enable it at some point, this is what you need:
netsh interface tcp set global autotuning level=enabled
netsh interface tcp set global rss=enabled
Additionally, you could try updating the firmware on your router/switch to see if that helps.
Finally, Microsoft apparently is aware of an issue with slow file copy operations and has a hotfix that supposedly fixes it. It has not been made generally available, but you can call them to get if you are experiencing the problem. Microsoft will usually waive the $59 fee when they realize you are having an actual problem that the hotfix will remedy. Note: You can find these “unreleased” hotfixes around the ‘net if you look.
This file copying mess has been a big annoyance for me. In fact, it has been my single major issue with Vista. However, after I follwed the first suggestion above, my file transfers have sped up dramatically. Good luck!
Technorati Tags: copy, files, hotfix, microsoft, network, vista, windows
Listen, I have to be honest. I didn’t read the post - way over my head, but just the fact that the most recent two posts were written in a span of FOUR minutes blows my mind. It takes me four minutes to write my name at 6:40 in the morning.
Ashley
April 27th, 2007
They were not actually written in that span.
I wrote the one on productivity Monday and just posted it this morning. The one on the router - I wrote that yesterday and I only wrote this one today. I just posted them so they show up today (meant to post the first two last night).
Zack Rippy
April 27th, 2007
Man, I know how you feel about the slow copying. I have tried to copy some Divx files over to my shared 500G drive on my file server and it is horribly slow due to the “calculating”. The file server is an XP box.
Philip
May 8th, 2007