How the problem that is described in the "Symptoms" section affects the installation of this update
This update will be installed correctly even if the computer is already affected by this problem. However, you may not be to install other updates until you install this update.
Filter manager and minifilters
The Filter Manager is a file system filter driver that Microsoft provides. This filter driver simplifies the development of third-party filter drivers. Filter Manager solves many of the problems with the existing legacy filter driver model. For example, Filter Manager can control load order through an assigned altitude. A filter driver developed to the Filter Manager model is called a minifilter. For more information about File System Filter drivers, visit the following Microsoft Web page:
Operating systems in which Filter Manager is available
Filter Manager is available in the following Microsoft operating systems:
- Windows XP Service Pack 2 (SP2)
- Windows Server 2003 SP1
- Windows Server 2003 R2
- All x64-based versions of Windows
- Windows 2000 SP4 and the hotfix that is described in one of the following Microsoft Knowledge Base articles:
891861 Update Rollup 1 for Windows 2000 SP4 and known issues
905590 A hotfix is available to add the new Filter Manager feature to computers that are running Windows 2000 Service Pack 4
How to determine whether you have a minifilter installed
To determine whether you have a minifilter installed, follow these steps:
- Click Start, click Run, type cmd, and then click OK.
- Type fltmc.exe, and then press ENTER.
A list of minifilters or of legacy filters and minifilters appears. The list that appears depends on the version of Fltmc.exe that is on the system.
The following example shows a legacy filter and minifilters:
Filter Name Num Instances Frame
------------------------------ ------------------ --------
TestLegacyFilter <Legacy>
TestMiniFilter1 4 1
TestMiniFilter2 0 0
In this example, TestLegacyFilter is a legacy filter. TestMiniFilter1 and TestMiniFilter2 are minifilters.
The following example shows only minifilters:
Filter Name Num Instances Frame
------------------------------ ------------------ --------
TestMiniFilter1 4 1
TestMiniFilter2 0 0
In this example, TestMiniFilter1 and TestMiniFilter2 are minifilters.
How to determine whether you are affected by this problem
If you experience the symptoms that are described in the "Symptoms" section, and you have a minifilter installed on the system, you may be affected by this problem.
Note We recommend that you install this update even if you do not have any minifilters installed. This is because we expect increased adoption of minifilter technology when Microsoft Windows Vista releases. If you install the update now, you will not be affected by this problem even if you install a minifilter-based product in the future.
Applications that install minifilters
Many companies are working on minifilter-based products. We do not know how many minifilter-based products have been released. Common applications that can use minifilter technology are antivirus and encryption programs. However, a variety of other applications can use minifilter technology. For example, Microsoft File Server Resource Manager and Microsoft Data Protection Manager use minifilter technology.
Known minifilters that cause this problem
The only minifilter-based application that we are currently aware of that can cause this problem is the Microsoft File Server Resource Manager (FSRM). FSRM is available only in Windows Server 2003 R2 and in Microsoft Windows Small Business Server 2003 R2.
Technical support for x64-based versions of Microsoft Windows
If your hardware came with a Microsoft Windows x64 edition already installed, your hardware manufacturer provides technical support and assistance for the Windows x64 edition. In this case, your hardware manufacturer provides support because a Windows x64 edition was included with your hardware. Your hardware manufacturer might have customized the Windows x64 edition installation by using unique components. Unique components might include specific device drivers or might include optional settings to maximize the performance of the hardware. Microsoft will provide reasonable-effort assistance if you need technical help with a Windows x64 edition. However, you might have to contact your manufacturer directly. Your manufacturer is best qualified to support the software that your manufacturer installed on the hardware. If you purchased a Windows x64 edition such as a Microsoft Windows Server 2003 x64 edition separately, contact Microsoft for technical support.
For product information about Microsoft Windows XP Professional x64 Edition, visit the following Microsoft Web site: For product information about x64-based versions of Microsoft Windows Server 2003, visit the following Microsoft Web site: 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