FIX: The Aspnet_wp.exe process may stop responding when you use the Response.BinaryWrite method to download large files from an ASP.NET page

When you use the Response.BinaryWrite method to download files that are 400 MB or larger from an ASP.NET page, the Aspnet_wp.exe process may stop responding (crash). You may see the following event logged in the application log of the Event Viewer:

In this scenario, the following things occur:

1. The code typically causes the download box to appear.
2. The Inetinfo.exe process starts to heavily exhaust memory.
3. Private Bytes in Inetinfo.exe increase until you run out of virtual memory.
4. When you run out of virtual memory, you experience an unexpected recycle of the Aspnet_wp.exe process. (Private Bytes in Aspnet_wp.exe are not affected; the number of Aspnet_wp.exe Private Bytes does not significantly increase.)
5. Inetinfo.exe does not release the memory until the download is complete (or canceled).

Note If you perform simultaneous downloads, you may compound the problem.

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next .NET Framework 1.0 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The English version of this hotfix has the file attributes (or later) 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.

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

This hotfix adds another function to the Response object (Response.TransmitFile). You can use the function instead of the BinaryWrite function or instead of other functions that are used to send files to the client. Also, you can use this function regardless of the size of the file that you want to transmit. To test this new functionality, paste the following code in an empty ASPX page after you download and install the hotfix. You must change the "c:\\repro\\z.zip" line in the code to reflect a path and ZIP file that exist on a computer.