FIX: You cannot download large files from an ASP.NET application on a computer that is running IIS 6.0


After you configure a Microsoft ASP.NET application on a computer that is running Microsoft Internet Information Services (IIS) 6.0, you experience the following symptoms:
  • If you try to transfer a large amount of data to the IIS 6.0 server, the transfer is not successful. When this behavior occurs, you receive the following error message:
    The underlying connection was closed: An unexpected error occurred on a receive.
  • If you view the %WINDIR%\System32\logfiles\Httperr#.log file, you notice a Timer_EntityBody entry that corresponds to the unsuccessful download operation.

    Note In this log file name, # represents the sequence number of the log file.


This problem occurs because the Http.sys kernel mode driver prematurely resets the connection to the Web server. Therefore, the file transfer operation is interrupted.


Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.


No prerequisites are required to install this hotfix.

Restart requirement

You do not have to restart your computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
   Date         Time   Version             Size   File name
20-Oct-2004 18:36 5.2.3790.224 335,872 Http.sys


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

More Information

Microsoft Windows Server 2003 Service Pack 1 (SP1) addresses all known timer-related issues including some issues that were found after the problem that is mentioned in this article.

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

For more information about additional logging properties that are available in the Httperr#.log file, click the following article number to view the article in the Microsoft Knowledge Base:

832975 Additional properties are now available for logging in the Httperr#.log file in IIS 6.0


ID do Artigo: 886461 - Última Revisão: 5 de jun de 2008 - Revisão: 1