Outlook Attachments Blocked
The Outlook E-Mail Security Update (included in Office 2000 Service Pack 2 and later versions) blocks access to .exe, .com and other "dangerous" files. See bottom for a list of the affected file types. You cannot open these files from Outlook, nor can you use Outlook to save them to your system. If you try to forward a message containing an .exe file, Outlook does not include the attachment in the forwarded message.
With the rash of recent viruses using *.zip files to get past antivirus filters and bypass Outlook's attachment block, you may want to add the zip extension to the Level1Remove key to force users to save zips to their hard drive before opening or block access to zip files completely by adding zip to the Level1Add key.
So what do you do when you receive an .exe file and must find a way to open it? There are several methods, depending on your version of Outlook.
Outlook 2003, Outlook 2002 and Outlook 2000 SP3 (but not Outlook 98 or earlier Outlook 2000 versions) allow the user to use a registry key to open up access to blocked attachments. (Always make a backup before editing the registry.) To use this key:
- Run Regedit, and go to this key:
HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook\Security (change 10.0 to 9.0 for Outlook 2000 SP3 or to 11.0 for Outlook 2003) - Under that key, add a new string value named Level1Remove.
- For the value for Level1Remove, enter a semicolon-delimited list of file extensions. For example, entering this:
.mdb;.url
would unblock Microsoft Access files and Internet shortcuts. Note that the use of a leading dot was not previously required, however, new security patches may require it. If you are using "mdb;url" format and extensions are blocked, add a dot to each extension. Note also that there is not a space between extensions.
If you are using this registry entry, a glance at Help | About Microsoft Outlook will show Security Mode: User Controlled above the license information.
To force users to save *.zip files to the hard drive before opening, add .zip to the extensions step 3. See How to configure Outlook to block additional attachment file name extensions for more information.
If you prefer not to edit the registry directly, you can use one of these tools to make the change; not all support both Outlook 2002 and 2000:
| File extension | File type |
| .ade | Microsoft Access project extension |
| .adp | Microsoft Access project |
| app | Microsoft Visual FoxPro application (blocked only in Outlook 2002 SP-2 and Outlook 2000 SP-3) |
| .asp | Active server page. (Blocked in Outlook 2002 SP3 and higher) |
| .asx | Windows Media Audio or Video shortcut (blocked only in Outlook 2002 builds earlier than 10.0.3005.x) |
| .bas | Visual Basic class module |
| .bat | Batch file |
| .cer | (blocked only in Outlook 2003 and later) |
| .chm | Compiled HTML Help file |
| .cmd | Windows NT Command script |
| .com | MS-DOS program |
| .cpl | Control Panel extension |
| .crt | Security certificate |
| .csh | KornShell script file (blocked only in Outlook 2002 SP-2 and Outlook 2000 SP-3 and later) |
| .exe | Program |
| fxp | Microsoft Visual FoxPro compiled program (blocked only in Outlook 2002 SP-2 and Outlook 2000 SP-3 and later) |
| .hlp | Help file |
| .hta | HTML program |
| .inf | Setup Information |
| .ins | Internet Naming Service |
| .isp | Internet Communication settings |
| .js | JScript Script file |
| .jse | Jscript Encoded Script file |
| .ksh | KornShell script file (blocked only in Outlook 2002 SP-2 and Outlook 2000 SP-3 and later) |
| .lnk | Shortcut |
| .mda | Microsoft Access add-in program (blocked only in Outlook 2002 and a patched version of Outlook 2000) |
| .mdb | Microsoft Access program |
| .mdt | Microsoft Access workgroup information (blocked only in Outlook 2002 SP-1 and Outlook 2000 SP-3 and later) |
| .mdw | Microsoft Access workgroup information (blocked only in Outlook 2002 SP-1 and Outlook 2000 SP-3 and later) |
| .mde | Microsoft Access MDE database |
| .mdz | Microsoft Access wizard program (blocked only in Outlook 2002 and a patched version of Outlook 2000) |
| .msc | Microsoft Common Console document |
| .msi | Windows Installer package |
| .msp | Windows Installer patch |
| .mst | Visual Test source files |
| .ops | Office XP settings (blocked only in Outlook 2002 SP-1 and and Outlook 2000 SP-3 later) |
| .pcd | Photo CD image |
| .pif | Shortcut to MS-DOS program |
| .prf | Microsoft Outlook profile settings (blocked only in Outlook 2002) |
| .prg | Microsoft Visual FoxPro program (blocked only in Outlook 2002 SP-2 and Outlook 2000 SP-3) |
| .pst | Microsoft Outlook Personal Folders file (blocked only in Outlook 2000 SP-3) |
| .reg | Registration entries |
| .scf | Windows Explorer command (blocked only in Outlook 2002) |
| .scr | Screen saver |
| .sct | Windows Script Component |
| .shb | Shell Scrap Object |
| .shs | Shell Scrap Object |
| .tmp | Temporary file. (Blocked in Outlook 2002 SP3 and higher) |
| .url | Internet shortcut |
| .vb | VBScript file |
| .vbe | VBScript encoded script file |
| .vbs | Visual Basic Script file |
| .vsmacros | Visual Studio .NET macro project file. (Blocked in Outlook 2002 SP3 and higher) |
| .vss | Visio shapes and Visio stencils (Blocked in Outlook 2002 SP3 and higher) |
| .vst | Visio template (Blocked in Outlook 2002 SP3 and higher) |
| .vsw | Visio workspace (Blocked in Outlook 2002 SP3 and higher) |
| .ws | Windows script file (Blocked in Outlook 2002 SP3 and higher) |
| .wsc | Windows Script Component |
| .wsf | Windows Script file |
| .wsh | Windows Script Host Settings file |