FIX: Memory leak in the W3wp.exe process for a WebDAV website when many WebDAV clients upload files, download files, or access file directories in WebDAV 7.5

Applies to: Internet Information Services 7.5

Symptoms


Consider the following scenario:
  • You install Microsoft WebDAV 7.5 for IIS on a computer that is running Internet Information Services (IIS) 7.0 or Internet Information Services (IIS) 7.5.
  • You enable the WebDAV feature on a website.
  • You create some WebDAV authoring rules.
  • Many WebDAV clients use the website to upload files, to download files, to access file directories, or to perform other operations that issue the WebDAV PROPFIND verb.
In this scenario, the memory usage for the W3wp.exe process becomes very large. Additionally, the computer that is running IIS might respond slower.

Cause


This issue occurs because of a memory leak in the Webdav.dll module.

Note The W3wp.exe process hosts the Webdav.dll module.

Resolution




Note
: A public hotfix for IIS 7.0 is not currently available. You may refer to the Workaround section to work around the issue. To obtain a private hotfix for IIS 7.0, you might have to create a separate service request.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that described in this article. Apply this hotfix only to systems that are experiencing the problem described in this article. 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 website: 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.


Prerequisites

To apply this hotfix, you must be running one of the following operating systems:
  • Windows 7
  • Windows 7 Service Pack 1 (SP1)
  • Windows Server 2008 R2
  • Windows Server 2008 R2 Service Pack 1 (SP1)
Additionally, you must have WebDAV 7.5 installed.

Restart requirement

You must restart the computer if the updated files are being used when you apply this hotfix. To avoid a restart of the computer, stop World Wide Web Publishing Service (W3wp.exe) before you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

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 item in Control Panel.

For all supported x86-based versions of Windows 7
File nameFile versionFile sizeDateTimePlatform
Webdav.dll7.5.7600.21020157,69602-Aug-201104:34x86
Webdav.dll7.5.7601.21782159,23202-Aug-201119:28x86
For all supported x64-based versions of Windows 7 and of Windows Server 2008 R2
File nameFile versionFile sizeDateTimePlatform
Webdav.dll7.5.7600.21020185,34402-Aug-201105:29x64
Webdav.dll7.5.7601.21782186,36802-Aug-201120:04x64
For all supported IA-64based versions of Windows Server 2008 R2
File nameFile versionFile sizeDateTimePlatform
Webdav.dll7.5.7600.21020457,72802-Aug-201104:14IA-64
Webdav.dll7.5.7601.21782460,28802-Aug-201104:14IA-64

Status


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

Workaround


To work around this issue, restart the IIS service.

More Information


For more information about how to install and configur WebDAV in IIS 7, visit the following Microsoft website:

Additional file information

Additional file information for Windows 7 and for Windows Server 2008 R2

Additional files for all supported x86-based versions of Windows 7
File nameUpdate.mum
File versionNot Applicable
File size2,868
Date (UTC)02-Aug-2011
Time (UTC)22:55
PlatformNot Applicable
File nameX86_0e1f78ec48f929392f9df8860c767397_31bf3856ad364e35_6.1.7601.21782_none_308dc0191151dbf4.manifest
File versionNot Applicable
File size706
Date (UTC)02-Aug-2011
Time (UTC)22:55
PlatformNot Applicable
File nameX86_e8d46320b7dc08d71a6a1f7bd89a31da_31bf3856ad364e35_6.1.7600.21020_none_4c3f50584f8c44e5.manifest
File versionNot Applicable
File size706
Date (UTC)02-Aug-2011
Time (UTC)22:55
PlatformNot Applicable
File nameX86_microsoft-windows-iis-webdavbinaries_31bf3856ad364e35_6.1.7600.21020_none_6aed25ecaa7ad423.manifest
File versionNot Applicable
File size4,743
Date (UTC)02-Aug-2011
Time (UTC)22:58
PlatformNot Applicable
File nameX86_microsoft-windows-iis-webdavbinaries_31bf3856ad364e35_6.1.7601.21782_none_6c94cbdca7cfe721.manifest
File versionNot Applicable
File size4,743
Date (UTC)02-Aug-2011
Time (UTC)22:58
PlatformNot Applicable
Additional files for all supported x64-based versions of Windows 7 and of Windows Server 2008 R2
File nameAmd64_9eeaa584e32f43a8e34b46d15302f7c4_31bf3856ad364e35_6.1.7601.21782_none_26cfd399c86e9087.manifest
File versionNot Applicable
File size1,062
Date (UTC)02-Aug-2011
Time (UTC)22:55
PlatformNot Applicable
File nameAmd64_fa4091b26afac76886370f8ac05d5ae9_31bf3856ad364e35_6.1.7600.21020_none_d0e136b6194c4262.manifest
File versionNot Applicable
File size1,062
Date (UTC)02-Aug-2011
Time (UTC)22:55
PlatformNot Applicable
File nameAmd64_microsoft-windows-iis-webdavbinaries_31bf3856ad364e35_6.1.7600.21020_none_c70bc17062d84559.manifest
File versionNot Applicable
File size4,749
Date (UTC)02-Aug-2011
Time (UTC)23:01
PlatformNot Applicable
File nameAmd64_microsoft-windows-iis-webdavbinaries_31bf3856ad364e35_6.1.7601.21782_none_c8b36760602d5857.manifest
File versionNot Applicable
File size4,749
Date (UTC)02-Aug-2011
Time (UTC)23:01
PlatformNot Applicable
File nameUpdate.mum
File versionNot Applicable
File size3,306
Date (UTC)02-Aug-2011
Time (UTC)22:55
PlatformNot Applicable
File nameWow64_microsoft-windows-iis-webdavbinaries_31bf3856ad364e35_6.1.7600.21020_none_d1606bc297390754.manifest
File versionNot Applicable
File size4,408
Date (UTC)02-Aug-2011
Time (UTC)23:01
PlatformNot Applicable
File nameWow64_microsoft-windows-iis-webdavbinaries_31bf3856ad364e35_6.1.7601.21782_none_d30811b2948e1a52.manifest
File versionNot Applicable
File size4,408
Date (UTC)02-Aug-2011
Time (UTC)23:01
PlatformNot Applicable
Additional files for all supported IA-64based versions of Windows Server 2008 R2
File nameIa64_5dc7063a82c1b95968df214550a29d78_31bf3856ad364e35_6.1.7600.21020_none_e2d93effeb39cd66.manifest
File versionNot Applicable
File size1,060
Date (UTC)02-Aug-2011
Time (UTC)22:55
PlatformNot Applicable
File nameIa64_6522d36ca2d5c9c66ddec75cac5e2719_31bf3856ad364e35_6.1.7601.21782_none_30dd320452ea97fe.manifest
File versionNot Applicable
File size1,060
Date (UTC)02-Aug-2011
Time (UTC)22:55
PlatformNot Applicable
File nameIa64_microsoft-windows-iis-webdavbinaries_31bf3856ad364e35_6.1.7600.21020_none_6aeec9e2aa78dd1f.manifest
File versionNot Applicable
File size4,746
Date (UTC)02-Aug-2011
Time (UTC)22:55
PlatformNot Applicable
File nameIa64_microsoft-windows-iis-webdavbinaries_31bf3856ad364e35_6.1.7601.21782_none_6c966fd2a7cdf01d.manifest
File versionNot Applicable
File size4,746
Date (UTC)02-Aug-2011
Time (UTC)22:55
PlatformNot Applicable
File nameUpdate.mum
File versionNot Applicable
File size2,347
Date (UTC)02-Aug-2011
Time (UTC)22:55
PlatformNot Applicable
File nameWow64_microsoft-windows-iis-webdavbinaries_31bf3856ad364e35_6.1.7600.21020_none_d1606bc297390754.manifest
File versionNot Applicable
File size4,408
Date (UTC)02-Aug-2011
Time (UTC)22:55
PlatformNot Applicable
File nameWow64_microsoft-windows-iis-webdavbinaries_31bf3856ad364e35_6.1.7601.21782_none_d30811b2948e1a52.manifest
File versionNot Applicable
File size4,408
Date (UTC)02-Aug-2011
Time (UTC)22:55
PlatformNot Applicable