Article ID: 919199 - View products that this article applies to.
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Microsoft Office Outlook 2007 includes a feature that blocks attachments that are considered unsafe. Custom code can query to verify whether Outlook considers a particular attachment to be blocked. The code does this by using the IAttachmentSecurity API.
Blocked attachmentsThe attachments that are blocked by Outlook 2007 can vary from client to client. Which attachments are blocked depends on how Outlook 2007 is configured and on policies that the administrator has applied.
For more information about how Outlook blocks attachments, click the following article number to view the article in the Microsoft Knowledge Base:
(https://support.microsoft.com/kb/829982/ )Cannot open attachments in Microsoft Outlook
The IAttachmentSecurity API exposes the IsAttachmentBlocked function. This function analyzes a file name. Then, the IsAttachmentBlocked function reports whether the file is considered to be blocked by Outlook. If the file is blocked, it is not shown in or indexed in Outlook 2007.
Definition of the IAttachmentSecurity API
Usage of the IAttachmentSecurity APIThis interface can be obtained by calling the QueryInterface function on the MAPI session object, requesting IID_IAttachmentSecurity. IsAttachmentBlocked will return "true" in "pfBlocked" if the attachment is considered blocked by Outlook, and therefore is not shown in or indexed in Outlook 2007.