Article ID: 2271150 - View products that this article applies to.
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When you try to open a linked file attachment in a Microsoft Outlook message, Outlook blocks access to the link. When the issue occurs, you may receive a message that resembles the following in the Outlook Information Bar:
Outlook blocked access to the following potentially unsafe attachments: filename.
The attachments that are affected by this issue are fairly uncommon. They are typically created by custom solutions by using Extended MAPI or the Outlook object model to add functionality to a Microsoft Exchange mailbox or to a local set of Outlook folders.
This issue occurs because, by default, Outlook 2010 and Outlook 2013 do not allow linked file attachments to be opened. Also, a July 2010 security update made a change to Outlook 2002, Outlook 2003, and Outlook 2007 to include this behavior.
For more information about this security update, click the following article number to view the article in the Microsoft Knowledge Base:
(https://support.microsoft.com/kb/978212/ )MS10-045: Vulnerability in Help and Support Center could allow remote code execution
For more information, visit the following Microsoft Security Response Center bulletin:
To work around this issue, use the following methods:
Outlook 2002 and earlier versions of Outlook allowed you to create linked attachments by using the Insert File command. However, this was only possible with messages that are formatted by using rich text. This feature is not available in newer versions of Outlook. However, you can insert hyperlinks in the body of the message instead.
The Outlook object model lets users create and send linked attachments. However, when these messages are sent, MAPI converts the linked attachment to an embedded attachment.
Because the overall matrix of scenarios is very large, and because Outlook also blocks other kinds of attachments, depending on the configuration, you should make sure to test the scenarios to see whether this issue may be related to unexpected behavior you may notice in Outlook. The best way to determine whether an attachment is a linked file is to use a MAPI-based tool such as MFCMAPI to check if the PR_ATTACH_METHOD property of the attachment is set to one of the following values:
To use MFCMAPI to determine whether an attachment is a linked attachment, follow these steps:
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http://www.codeplex.com/mfcmapiThe third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.
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Article ID: 2271150 - Last Review: March 15, 2013 - Revision: 1.3