Attachment file types restricted by Outlook 2010
Applies to: Office 2010
Topic Last Modified: 2012-02-29
Some attachments in items (such as e-mail messages or appointments) in Microsoft Outlook 2010 have restricted access. Files that have specific extensions 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).
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This article is for IT Professionals. If you’re not an IT Professional, but want to learn more about how to share files that have restricted file types, see Blocked attachments in Outlook (https://go.microsoft.com/fwlink/p/?LinkId=188575).
By default, Outlook 2010 classifies several file types as Level 1 and blocks files that have 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. There are no Level 2 file types by default. For more information, see Plan attachment settings in Outlook 2010.
The following table lists Level 1 file types that are blocked under a default installation of Outlook 2010.
| File extension | File type |
|---|---|
.ade |
Microsoft Access project extension |
.adp |
Microsoft Access project |
.app |
Application file |
.asp |
Active server page |
.bas |
Microsoft Visual Basic class module |
.bat |
Batch file |
.cer |
Internet Security Certificate file |
.chm |
Compiled HTML Help file |
.cmd |
DOS CP/M command file, Microsoft Windows NT command script |
.cnt |
Windows Help contents file |
.com |
Microsoft MS_DOS program |
.cpl |
Control Panel extension |
.crt |
Security certificate |
.csh |
Script file |
.der |
DER Encoded X509 certificate file |
.exe |
Executable file |
.fxp |
Microsoft Visual FoxPro compiled program |
.gadget |
Windows Gadget |
.grp |
Windows program group file |
.hlp |
Help file |
.hpj |
Help project file |
.hta |
HTML program |
.inf |
Information or setup file |
.ins |
Internet Naming Service |
.isp |
Internet Communication settings |
.its |
Internet Document Set file |
.jar |
JAVA archive file |
.js |
JavaScript source code |
.jse |
JScript Encoded script file |
.ksh |
UNIX Shell script file |
.lnk |
Windows shortcut |
.mad |
Microsoft Access module shortcut |
.maf |
Microsoft Access shortcut |
.mag |
Microsoft Access diagram shortcut |
.mam |
Microsoft Access macro shortcut |
.maq |
Microsoft Access query shortcut |
.mar |
Microsoft Access report shortcut |
.mas |
Microsoft Access stored procedures |
.mat |
Microsoft Access table shortcut |
.mau |
Media attachment unit |
.mav |
Microsoft Access view shortcut |
.maw |
Microsoft Access data access page |
.mcf |
Manifest configuration file |
.mda |
Microsoft Access add-in program |
.mdb |
Microsoft Access program |
.mde |
Microsoft Access MDE database file |
.mdt |
Microsoft Access data file |
.mdw |
Microsoft Access workgroup |
.mdz |
Microsoft Access wizard program |
.msc |
Microsoft Common Console document |
.msh |
Windows PowerShell script helper |
.msh1 |
Windows PowerShell script helper |
.msh2 |
Windows PowerShell script helper |
.mshxml |
Windows PowerShell script helper |
.msh1xml |
Windows PowerShell script helper |
.msh2xml |
Windows PowerShell script helper |
.msi |
Windows Installer package |
.msp |
Windows Installer update package file |
.mst |
Visual Test source file |
.ops |
Microsoft Office profile settings file |
.osd |
Open software description file |
.pcd |
Microsoft Visual Test compiled script |
.pif |
Windows program information file |
.pl |
Perl script file |
.plg |
Developer Studio build log |
.prf |
Outlook profile file |
.prg |
Program source file |
.ps1 |
Windows PowerShell |
.ps1xml |
Windows PowerShell |
.ps2 |
Windows PowerShell |
.ps2xml |
Windows PowerShell |
.psc1 |
Windows PowerShell |
.psc2 |
Windows PowerShell |
.pst |
Microsoft Outlook personal folder file |
.reg |
Registration entries, Registry data file |
.scf |
Windows Explorer command file |
.scr |
Windows screen saver |
.sct |
Windows script component |
.shb |
Windows shortcut to a document |
.shs |
Shell Scrap object file |
.tmp |
Temporary file or folder |
.url |
Uniform Resource Locator (Internet shortcut) |
.vb |
Microsoft Visual Basic Scripting Edition (VBScript) file |
.vbe |
VBScript Encoded script file |
.vbp |
Visual Basic project file |
.vbs |
VBScript script file, Visual Basic for Applications script file |
.vsmacros |
Microsoft Visual Studio .NET binary-based macro project file |
.vsw |
Microsoft Visio workspace file |
.ws |
Windows script file |
.wsc |
Windows script component |
.wsf |
Windows script file |
.wsh |
Windows Script Host settings file |
.xbap |
XAML browser application |
.xnk |
Microsoft Exchange public folder shortcut |