AD DS database size increases significantly when the Credential Roaming feature is enabled in Windows Vista, in Windows 7, in Windows Server 2008 or in Windows Server 2008 R2

When you enable the Credential Roaming feature in a domain, the size of the Active Directory Domain Services (AD DS) database increases significantly.

Additionally, you may experience performance issues that are related to AD DS when this issue occurs. For example, you may experience LDAP query delays or replication delays.

This issue occurs because unnecessary credential information is stored for each user in the domain. Some of this credential information may not have to be roamed. The effect of storing unnecessary credential information is proportional to the number of users. Therefore, when many users exist in a domain, the size of the AD DS database increases significantly. Additionally, the complete AD DS database (Ntds.dit) may not be loaded into memory on the domain controllers. Therefore, you may experience the performance issues that are described in the "Symptoms" section.

Note The credential information of each domain user is added to the AD DS database in order to enable the Credential Roaming feature.

After you install the hotfix, the Credential Roaming feature filters user credentials before it uploads them. This behavior prevents the addition of unnecessary credential information to the AD DS database.

A filtering layer is added to filter out the following credential information:

• Keys that are not associated with a certificate
• Data Protection API (DPAPI) keys that do not protect a roamed private key binary large object (BLOB)
• Smart card certificates

The following registry entries can be added under the HKEY_CURRENT_USER\Software\Policies\Microsoft\Cryptography\AutoEnrollment subkey to control whether the Credential Roaming feature filters the credential information: Notes

• This hotfix does not affect credentials that have already roamed to an Active Directory in which the Credential Roaming feature is enabled.
• By default, the following items do not roam when you enable the Credential Roaming feature after you install this hotfix:
  • Smart card certificates
  • DPAPI keys
  • Other keys that are not associated with certificates
• You must install this hotfix on all client computers that roam credential information to the AD DS database.

Hotfix information

Important This hotfix has been re-released to address an issue in which the digital signature on files produced and signed by Microsoft will expire prematurely, as described in Microsoft Security Advisory 2749655.

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 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 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.

Prerequisites

To apply this hotfix, you must be running one of the following operating systems:

• Windows Vista Service Pack 2 (SP2)
• Windows Server 2008 Service Pack 2 (SP2)
• Windows 7
• Windows 7 Service Pack 1 (SP1)
• Windows Server 2008 R2
• Windows Server 2008 R2 Service Pack 1 (SP1)

For more information about how to obtain a Windows Vista service pack, click the following article number to view the article in the Microsoft Knowledge Base: For more information about how to obtain a Windows Server 2008 service pack, click the following article number to view the article in the Microsoft Knowledge Base: For more information about how to obtain a Windows 7 or Windows Server 2008 R2 service pack, click the following article number to view the article in the Microsoft Knowledge Base:

Registry information

To use the hotfix in this package, you do not have to make any changes to the registry.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The global version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.

Windows Vista and Windows Server 2008 file information notes

Important Windows Vista hotfixes and Windows Server 2008 hotfixes are included in the same packages. However, only "Windows Vista" is listed on the Hotfix Request page. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows Vista" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each hotfix applies to.

• The files that apply to a specific product, SR_Level (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table.
  Collapse this tableExpand this table

  Version	Product	SR_Level	Service branch
  6.0.600 2 . 22xxx	Windows Vista and Windows Server 2008	SP2	LDR

• The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2008 and for Windows Vista" section. MUM files and MANIFEST files, and the associated security catalog (.cat) files, are extremely important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.

For all supported x86-based versions of Windows Server 2008 and of Windows Vista

For all supported x64-based versions of Windows Server 2008 and of Windows Vista

For all supported IA-64-based versions of Windows Server 2008

Windows 7 and Windows Server 2008 R2 file information notes

• The files that apply to a specific product, milestone (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:
  Collapse this tableExpand this table

  Version	Product	Milestone	Service branch
  6.1.760 0.21xxx	Windows 7 and Windows Server 2008 R2	RTM	LDR
  6.1.760 1.22xxx	Windows 7 and Windows Server 2008 R2	SP1	LDR

• The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2008 R2 and for Windows 7" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are extremely important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.

For all supported x86-based versions of Windows 7

For all supported x64-based versions of Windows 7 and of Windows Server 2008 R2

For all supported IA-64-based versions of Windows Server 2008 R2

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

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base: For more information about the Credential Roaming feature in AD DS, visit the following Microsoft TechNet website:For more information about how to configure and troubleshoot Certificate Services Client–Credential Roaming, visit the following Microsoft TechNet website:For more information about how to use credential roaming, visit the following Microsoft TechNet website:To remove previously roamed content from AD DS as part of deploying the hotfix, follow these steps:

1. Disable the Credential Roaming feature on all client computers.
2. Back up the AD DS database.
3. Delete the Credential Roaming attributes in the AD.
   
   Note For more information about how to delete the Credential Roaming attributes, visit the following Microsoft TechNet website:
   How to decommission credential roaming

   (http://technet.microsoft.com/library/cc700809.aspx)
4. Install the hotfix on all client computers.
5. Enable the Credential Roaming feature.

Additional file information

Additional file information for Windows Vista and for Windows Server 2008

Additional files for all supported x86-based versions of Windows Vista and of Windows Server 2008

Additional files for all supported x64-based versions of Windows Vista and of Windows Server 2008

Additional files for all supported IA-64-based versions of Windows Server 2008

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

Additional files for all supported x86-based versions of Windows 7

Additional files for all supported x64-based versions of Windows 7 and of Windows Server 2008 R2

Additional files for all supported IA-64-based versions of Windows Server 2008 R2