Slow Windows Explorer Fix

Intro

I put this page up because the only place that documented this problem was a site which charges for access to the solution. I hope this saves someone the time and frustration that I went through.

-- Brent Plump (22-Nov-06)

Symptoms

When opening any files on the local file system, there is a pause of about 10-15 seconds before the file will open.
When right-clicking on files in the local file system, there is a similar delay of about 10-15 seconds before the context menu will appear.
All delays disappear if the computer is disconnected from the network.
This happens on Windows XP (though I wouldn't be surprised if it happened on NT/2000, too)

Solution

Open a command prompt and use the netstat -an command. This prints a list of machines you currently have connections to.
Go to explorer and open a file.
While you are waiting for the file to open, run netstat -an again and look for new entries. The problem-causing entry should look something like:TCP 192.168.1.101:2594 192.168.1.20:445 SYN_SENT
The IP address on the left is your local machine's. The IP address on the right is the machine it is trying to connect to (but unable to). Copy this IP address (without the port number) and search for it with regedit.
In my case, the offending entries were stored under HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\UserAssist\{xxxxxxxxxxxxx}\Count

Cause

I caused the problem when I fooled around with some samba settings on my file server and then moved the file server to a new IP address. In other cases I've read about, an application server or domain controller was moved off the network when the problems started appearing.

For some reason, the other Windows machines on the network cached the old IP address of the file server and were polling it for information whenever a file or the context menu is opened.