Occasionally this is a frustration for some of my users. They want to be able to send and receive files which are normally restricted. Executables, batch files, registry files, etc. Rather than try to instruct them in the fine arts of ZIP and FTP, I'd rather just open their machines up to catastrophic possibilities and grant them the ability to send and receive these files. This is purely motivated by me not wanting to be hassled with this anymore.
There are two security levels built into Outlook when it comes to file attachments. The first level is configurable by the user - these attachments can be saved from an e-mail message to the machine's hard drive. The second set of security restrictions is more strict - no file in this group is allowed to be interacted with in Outlook. You simply can not send or receive these files and there is no way to change this.
Well, there actually IS a way to change it, but nothing out of the box. If you want to change the Outlook file attachments security levels, you can either download the
Outlook Permissions Add-in or you can make the following changes to your systems registry:
1. Start...Run..."regedit"
2. Go to HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\Security
4. Create a new string value called Level1Remove
5. Enter in the file extensions you want to use, such as .exe or .bat
6. You can have multiple file types separated by a semicolon like this: ".exe;.com"
The following are a list of the file attachments that are restricted by default
.ade Microsoft Access project extension
.adp Microsoft Access project
.asx Windows Media Audio / Video
.bas Microsoft Visual Basic class module
.bat Batch file
.chm Compiled HTML Help file
.cmd Microsoft Windows NT Command script
.com Microsoft MS-DOS program
.cpl Control Panel extension
.crt Security certificate
.exe Program
.hlp Help file
.hta HTML program
.inf Setup Information
.ins Internet Naming Service
.isp Internet Communication settings
.js JScript file
.jse Jscript Encoded Script file
.lnk Shortcut
.mdb Microsoft Access program
.mde Microsoft Access MDE database
.msc Microsoft Common Console document
.msi Microsoft Windows Installer package
.msp Microsoft Windows Installer patch
.mst Microsoft Windows Installer transform; Microsoft Visual Test source file
.pcd Photo CD image; Microsoft Visual compiled script
.pif Shortcut to MS-DOS program
.prf Microsoft Outlook profile settings
.reg Registration entries
.scf Windows Explorer command
.scr Screen saver
.sct Windows Script Component
.shb Shell Scrap object
.shs Shell Scrap object
.url Internet shortcut
The above registry list and file extensions were taken from here.