When you enable the "Encrypt the Offline Files cache" policy setting, multiple EFS certificates may be generated when you log on to the domain from multiple Windows Vista-based or Windows Server 2008-based client computers

If Credential Roaming is enabled, it is possible that requests for Encrypting File System (EFS) certificates, to encrypt the files in the offline cache, will be made before existing certificates are synced from the user object in Active directory to the user's local computer certificate store.

This behavior occurs if encryption of the offline files cache is enabled and if folder redirection is being implemented by Group Policy settings.

This behavior results in multiple EFS certificates being generated and stored in the following locations:

• The personal certificate store on the local computer where you log on to the domain
• The credential roaming attributes of the user object in Active Directory

The following issues may occur because of this behavior:

• When a user logs on to a Windows Vista-based workstation or a Windows Server 2008-based server in the domain, a new certificate request for File System (EFS) certificates is generated.
• The user object in Active Directory becomes bloated. Certain operations may fail because of the size of the user object.
• Users who log on to many workstations experience limitations according to the number of "non link-valued" attributes and the LDAP limit of 10 MB for the "Max LDAP receive buffer."
• Credential roaming fails if the Maximum number of roaming credentials per user setting or the Maximum size (in bytes) of a roaming credential setting is exceeded.

Note This problem does not occur when you log on to the domain from a Windows XP-based client computer.

When a user logs on to a Windows Vista-based computer, the winlogon process waits for the Group Policy process to finish before the winlogon process sends a notification to the Service Control Manager that the user logged on. The credential roaming components are triggered when the Service Control Manager receives the notification that the user logged on. This process then synchronizes the certificates that are held in Active Directory for the user who is logging on with the user-associated certificate store on the local computer.

If folder redirection is implemented by using Group Policy and if the target shares are configured to be made available offline, the CSC components are invoked when the Group Policy settings are applied. In this scenario, the credential roaming components will not yet have been triggered because the Service Control Manager has not received the notification that the user has logged on.

If the offline cache is configured to be encrypted, the CSC components make a call into EFS to make sure that the cached files are encrypted.

If the credential roaming components are not triggered yet and if the user does not have a suitable certificate in the personal certificate store on the local computer, a new EFS certificate request is generated.

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 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.

Important Windows Vista and Windows Server 2008 hotfixes are included in the same packages. However, only one of these products may be listed on the �Hotfix Request� page. To request the hotfix package that applies to both Windows Vista and Windows Server 2008, just select the product that is listed on the page.

Prerequisites

To apply this hotfix on a Windows Vista-based computer, you must have Windows Vista Service Pack 1 (SP1) installed. For more information, click the following article number to view the article in the Microsoft Knowledge Base: No prerequisites are required for a Windows Server 2008-based computer.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

Registry information

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base: Follow these steps:

1. Start Registry Editor. To do this, click Start, type regedit in the Start Search box, and then press ENTER.
2. Locate and then right-click the following registry subkey:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\EFS
3. Point to New, and then click DWORD Value.
4. Type NoEnroll, and then press ENTER.
5. Right-click NoEnroll, and then click Modify.
6. In the Value data box, type 0x1, and then click OK.
7. Exit Registry Editor.

Note After you set the NoEnroll entry to "1", the encryption of new entries will not be put into the offline cache until the credential roaming task has completed.

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.

Windows Vista and Windows Server 2008 file information notes

The .manifest files and the .mum files that are installed in each environment are listed separately in the "Additional file information for Windows Server 2008 and for Windows Vista" section. These files and their associated .cat (security catalog) files are critical to maintaining the state of the updated component. The .cat files are signed with a Microsoft digital signature. The attributes of these security files are not listed.

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

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

For more information about folder redirection and about Offline Files, visit the following Microsoft Web sites:For more information about credential roaming, visit the following Microsoft Web sites:For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:

Additional file information for Windows Server 2008 and for Windows Vista

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

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

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