Consider the following scenario:
- You try to encrypt an Encrypting File System (EFS) file on a Windows XP-based computer.
- No EFS certificate is available in the local certificate store.
- No certification authority (CA) is available to issue an EFS certificate.
In this scenario, EFS generates a self-signed certificate. Then, EFS uses this self-signed certificate to encrypt the file.
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 this specific problem. 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.
To apply this hotfix, you must have Windows XP Service Pack 2 (SP2) installed on the computer.
You must restart the computer after you apply this hotfix.
Hotfix replacement information
This hotfix does not replace a previously released hotfix.
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.
Collapse this tableExpand this table
|File name||File version||File size||Date||Time||Platform||SP requirement||Service branch|
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
After you apply the hotfix, you can prevent EFS from generating self-signed certificates. To do this, follow these steps. Warning
Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.
- Click Start, click Run, type regedit, and then click OK.
- Locate and then click the following registry subkey:
- On the Edit menu, point to New, and then click DWORD Value.
- Type EfsOptions, and then press ENTER.
- Double-click EfsOptions, type 0 in the Value data box, and then click OK.
- Exit Registry Editor.
After you add the EfsOptions registry value, you must create a custom Administrative Template to define a new policy. This new policy will centrally manage the registry change. To do this, follow these steps:
- Start Notepad.
- Enter the following text.
CATEGORY "Public Key Policies"
POLICY "Encrypted File System"
KEYNAME "Software\Policies\Microsoft\Windows NT\CurrentVersion\EFS"
PART "Allow EFS to Generate Selfsigned Certificate when a Certificate Authority is not available" CHECKBOX
VALUEON NUMERIC 4
VALUEOFF NUMERIC 0
- On the File menu, click Save As.
- In the Save as typelist, click All Files.
- Type %windir%\inf\efscustom.adm in the File name box, and then click Save.
Note The %windir% placeholder represents the drive letter of the Windows system folder.
- Exit Notepad.
- Restart the computer.
After you apply this hotfix, you may still experience the old behavior if the EfsOptions registry value is missing or is set to a value of 4.
For more information about how to create custom Administrative Templates, click the following article number to view the article in the Microsoft Knowledge Base:
How to create custom Administrative Templates in Windows 2000
For more information, click the following article number to view the article in the Microsoft Knowledge Base:
You cannot prevent EFS from generating a self-signed certificate when you try to encrypt an EFS file on a Windows Server 2003-based computer
For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
Description of the standard terminology that is used to describe Microsoft software updates