Updated: 2009-04-09

There is restricted access to some attachments in items (such as e-mail messages or appointments) in Microsoft Office Outlook 2007. Files with specific file types can be categorized as Level 1 (the user cannot view the file) or Level 2 (the user can open the file after saving it to disk).

NoteNote:

This topic is for Outlook administrators. To learn more about why some Outlook attachments are blocked, see Blocked attachments: The Outlook feature you love to hate. Or learn how to share files with restricted file types by reading Blocked attachments in Outlook.

By default, Outlook classifies a number of file type extensions as Level 1 and blocks files with those extensions from being received by users. As an administrator, you can use Group Policy to manage how a file type is categorized for e-mail attachment blocking. For example, you can change a file type categorization from Level 1 to Level 2 or create a list of Level 2 file types.

NoteNote:

There are no Level 2 file types by default.

You can find links to more information about customizing attachment settings in Outlook in the See Also section, which is visible when you are connected to the Internet.

The following table lists Level 1 file types that are blocked under a default installation of Outlook.

File type File description

.ade

Access Project Extension (Microsoft)

.adp

Access Project (Microsoft)

.app

Executable Application

.asp

Active Server Page

.bas

BASIC Source Code

.bat

Batch Processing

.cer

Internet Security Certificate File

.chm

Compiled HTML Help

.cmd

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

.com

Command

.cpl

Windows Control Panel Extension (Microsoft)

.crt

Certificate File

.csh

csh Script

.der

DER Encoded X509 Certificate File

.exe

Executable File

.fxp

FoxPro Compiled Source (Microsoft)

.hlp

Windows Help File

.hta

Hypertext Application

.inf

Information or Setup File

.ins

IIS Internet Communications Settings (Microsoft)

.isp

IIS Internet Service Provider Settings (Microsoft)

.its

Internet Document Set, International Translation

.js

JavaScript Source Code

.jse

JScript Encoded Script File

.ksh

UNIX Shell Script

.lnk

Windows Shortcut File

.mad

Access Module Shortcut (Microsoft)

.maf

Access (Microsoft)

.mag

Access Diagram Shortcut (Microsoft)

.mam

Access Macro Shortcut (Microsoft)

.maq

Access Query Shortcut (Microsoft)

.mar

Access Report Shortcut (Microsoft)

.mas

Access Stored Procedures (Microsoft)

.mat

Access Table Shortcut (Microsoft)

.mau

Media Attachment Unit

.mav

Access View Shortcut (Microsoft)

.maw

Access Data Access Page (Microsoft)

.mda

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

.mdb

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

.mde

Access MDE Database File (Microsoft)

.mdt

Access Add-in Data (Microsoft)

.mdw

Access Workgroup Information (Microsoft)

.mdz

Access Wizard Template (Microsoft)

.msc

Microsoft Management Console Snap-in Control File (Microsoft)

.msh

Windows PowerShell

.msh1

Windows PowerShell

.msh2

Windows PowerShell

.mshxml

Windows PowerShell

.msh1xml

Windows PowerShell

.msh2xml

Windows PowerShell

.msi

Windows Installer File (Microsoft)

.msp

Windows Installer Patch

.mst

Windows SDK Setup Transform Script

.ops

Office Profile Settings File

.pcd

Visual Test (Microsoft)

.pif

Windows Program Information File (Microsoft)

.plg

Developer Studio Build Log

.prf

Outlook Profile file

.prg

Program File

.ps1

Windows PowerShell

.ps1xml

Windows PowerShell

.ps2

Windows PowerShell

.ps2xml

Windows PowerShell

.psc1

Windows PowerShell

.psc2

Windows PowerShell

.pst

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

.reg

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

.scf

Windows Explorer Command

.scr

Windows Screen Saver

.sct

Windows Script Component, Foxpro Screen (Microsoft)

.shb

Windows Shortcut into a Document

.shs

Shell Scrap Object File

.tmp

Temporary File/Folder

.url

Internet Location

.vb

VBScript File or Any VisualBasic Source

.vbe

VBScript Encoded Script File

.vbs

VBScript Script File, Visual Basic for Applications Script

.vsmacros

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

.vsw

Visio Workspace File (Microsoft)

.ws

Windows Script File

.wsc

Windows Script Component

.wsf

Windows Script File

.wsh

Windows Script Host Settings File

.xnk

Exchange Public Folder Shortcut

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This topic is included in the following downloadable books for easier reading and printing:

See the full list of available books at Downloadable content for the 2007 Office Resource Kit .

See Also