Blocked attachments in Outlook

To help protect your computer, Microsoft Outlook 2010 does not allow you to receive files of certain types (such as .exe files) as attachments, because of their potential for introducing a virus into your computer. Outlook blocks these files by default. See the section Attachment file types blocked in Outlook for a list of the file types blocked.

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Share your files safely

Change which file types are blocked

Attachment file types blocked in Outlook

Share your files safely

If you want to receive a file of a type that is blocked by Outlook, you can ask the sender to either make the file accessible without using Outlook, or make it less likely to be blocked by Outlook. Following are a few safe ways to share files with people you trust.

Use a shared server    You might want to ask the sender to save the attachment to a server or an FTP site that you can access. This can include a secure network share server such as SharePoint. The sender can send you a link to the attachment on the server or FTP site. You can click the link to access the file and save it on your computer.

Use a file compression utility    Using a compression utility, such as WinZip, creates a compressed archive file that has a different file name extension. Outlook does not recognize these file name extensions as potential threats. Therefore, it does not block the new attachment. Many third-party compression utilities are available.

Rename the file    You can request that the sender rename the attachment to use a file name extension that Outlook does not recognize as a threat. For example, an executable file that has the file name extension .exe could be renamed as a Word 2010 file that has a .docx file name extension.

Ask the sender to resend the renamed attachment to you. To save the attachment and rename it to use the original file name extension, do the following:

  1. Locate the attachment in the email message.

  2. Right-click the attachment, and then click Copy.

  3. Right-click the desktop, and then click Paste.

  4. Right-click the pasted file, and then click Rename.

  5. Rename the file to use the original file name extension, such as .exe.

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Change which file types are blocked

If you use a Microsoft Exchange Server account and the Exchange Server administrator has configured the Outlook security settings, the administrator might be able to help you. Ask the administrator to adjust the security settings on your mailbox to accept attachments such as the one that Outlook blocked.

If you do not use an Exchange Server account, there is an advanced procedure that you can use to unblock some file types. This procedure involves editing the registry in Windows. For more information about unblocking attachment file types, see the Microsoft Support article on blocked attachments in Outlook.

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Attachment file types blocked in Outlook

File name extension

File type


Access Project Extension (Microsoft)


Access Project (Microsoft)


Executable Application


Active Server Page


BASIC Source Code


Batch Processing


Internet Security Certificate File


Compiled HTML Help


DOS CP/M Command File, Command File for Windows NT




Windows Control Panel Extension (Microsoft)


Certificate File


csh Script


DER Encoded X509 Certificate File


Executable File


FoxPro Compiled Source (Microsoft)


Windows Vista gadget


Windows Help File


Hypertext Application


Information or Setup File


IIS Internet Communications Settings (Microsoft)


IIS Internet Service Provider Settings (Microsoft)


Internet Document Set, Internet Translation


JavaScript Source Code


JScript Encoded Script File


UNIX Shell Script


Windows Shortcut File


Access Module Shortcut (Microsoft)


Access (Microsoft)


Access Diagram Shortcut (Microsoft)


Access Macro Shortcut (Microsoft)


Access Query Shortcut (Microsoft)


Access Report Shortcut (Microsoft)


Access Stored Procedures (Microsoft)


Access Table Shortcut (Microsoft)


Media Attachment Unit


Access View Shortcut (Microsoft)


Access Data Access Page (Microsoft)


Access Add-in (Microsoft), MDA Access 2 Workgroup (Microsoft)


Access Application (Microsoft), MDB Access Database (Microsoft)


Access MDE Database File (Microsoft)


Access Add-in Data (Microsoft)


Access Workgroup Information (Microsoft)


Access Wizard Template (Microsoft)


Microsoft Management Console Snap-in Control File (Microsoft)


Microsoft Shell


Microsoft Shell


Microsoft Shell


Microsoft Shell


Microsoft Shell


Microsoft Shell


Windows Installer File (Microsoft)


Windows Installer Update


Windows SDK Setup Transform Script


Office Profile Settings File


Visual Test (Microsoft)


Windows Program Information File (Microsoft)


Developer Studio Build Log


Windows System File


Program File


MS Exchange Address Book File, Outlook Personal Folder File (Microsoft)


Registration Information/Key for W95/98, Registry Data File


Windows Explorer Command


Windows Screen Saver


Windows Script Component, Foxpro Screen (Microsoft)


Windows Shortcut into a Document


Shell Scrap Object File


Windows PowerShell


Windows PowerShell


Windows PowerShell


Windows PowerShell


Windows PowerShell


Windows PowerShell


Temporary File/Folder


Internet Location


VBScript File or Any Visual Basic Source


VBScript Encoded Script File


VBScript Script File, Visual Basic for Applications Script


Visual Studio .NET Binary-based Macro Project (Microsoft)


Visio Workspace File (Microsoft)


Windows Script File


Windows Script Component


Windows Script File


Windows Script Host Settings File


Exchange Public Folder Shortcut

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Applies To: Outlook 2010

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