Overlapped I/O Operation Is in Progress (187770)


The information in this article applies to:

  • Microsoft Internet Explorer 4.0 for Windows NT 4.0
  • Microsoft Internet Explorer 4.0 for Windows 95
  • the operating system: Microsoft Windows 98
This article was previously published under Q187770

SYMPTOMS

When you try to use Internet Explorer version 4.0 with Internet Explorer Service Pack 1 installed to access a File Transfer Protocol (FTP) or Gopher site, Internet Explorer may stop responding (hang). Also, you may receive an error message similar to the following error message:
Internet Explorer cannot open the Internet site Web address. Overlapped I/O operation is in progress.

CAUSE

This behavior can occur if you are using a proxy auto-configuration script. The following is an example of a proxy auto-configuration script that may cause the error: 
   function FindProxyForURL(url, host)
       {
           if (isPlainHostName(host) || dnsDomainIs(host, ".msn.com"))
                 return "DIRECT";
           else
                 return "PROXY gproxy:80; DIRECT";
        }
The overlapped input/output error is caused by not transitioning properly from a proxy attempt to a DIRECT attempt.

RESOLUTION

To resolve this problem, obtain and install Internet Explorer 4.01 Service Pack 2. You can obtain Internet Explorer 4.01 Service Pack 2 from the following Microsoft Web site:

http://www.microsoft.com/windows/ie/downloads/default.mspx



To work around this problem, follow these steps:

  1. In Internet Explorer, click Internet Options on the View menu.
  2. Click the Connection tab.
  3. Click Configure, delete the text in the URL box, and then click OK.
  4. Click to select the Access the Internet using a proxy server check box, and then type the proxy server address and port.

    NOTE
    • You may need to obtain this information from your network administrator.
  5. Click OK.
For more information about how to configure Internet Explorer to use a proxy server, please see the following article in the Microsoft Knowledge Base: How to Configure Internet Explorer to Use a Proxy Server

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

MORE INFORMATION

A limitation still exists because File Transfer Protocol (FTP) and Gopher connections are unable to try a combination of proxies and DIRECT during the same download attempt. For FTP and Gopher scenarios, if FindProxyForUrl returns a list such as: 

   PROXY proxy1; PROXY proxy2; ...; PROXY proxyN; DIRECT


and all N proxies do not connect, then Wininet does not correctly try the DIRECT case. You still receive an error message, but if you try the same Web address (URL) again, the DIRECT case is then tried. Ideally, requests normally go through a proxy server, so you are unlikely to experience this. Also, this issue is not reproducible if DIRECT is used alone.
Modification Type:MinorLast Reviewed:11/15/2005
Keywords:kbHotfixServer kbQFE kbenv kbnetwork kbprb KB187770
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