You are prompted for your smart card when you try to send an encrypted e-mail message in Microsoft Office Outlook 2007, Microsoft Outlook 2010, or Microsoft Outlook 2013. This problem occurs when you add yourself or a distribution list that contains your account to the recipient list.
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:
322756 How to back up and restore the registry in Windows
To resolve this problem, follow these steps:
If you are using Outlook 2007, apply hotfix package 978401. If you are using Outlook 2010 or Outlook 2013, skip to step 2.
For more information about the hotfix, click the following article number to view the article in the Microsoft Knowledge Base:
978401 Description of the Office Outlook 2007 hotfix package (Outlook-x-none.msp): February 23, 2010
Enable the AllowPrivateKeyCheck registry value. To do this, follow these steps:
In Windows Vista, Click Start, type regedit in the Start Search box, and then press Enter.
If you are prompted for an administrator password or for confirmation, type the password, or provide confirmation.
In Windows XP, click Start, click Run, type regedit in the Open box, and then click OK.
Locate and then click the following registry subkey, based on the version of Outlook that is installed:
Outlook 2007: HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\Security
Outlook 2010: HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Security
Outlook 2013: HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Security
On the Edit menu, point to New, and then click DWORD Value.
Type AllowPrivateKeyCheck, and then press Enter.
Right-click AllowPrivateKeyCheck, and then click Modify.
In the Value data box, type 0, and then click OK.
Exit Registry Editor.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.