How do you unblock attachments in Outlook 2002?

This article can be also found at support.microsoft.com and enter article number Q290497.

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The information in this article applies to:
- Microsoft Outlook 2002
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SUMMARY
=======
Outlook 2002 includes a new security feature that blocks attachments considered unsafe. If you receive an e-mail message that contains one of the blocked file types, you may see the following warning message:

Outlook blocked access to the following potentially unsafe attachments: [...]

Although access to the attachment has been blocked, the attachment still exists in the message. This article summarizes what to do if you need to access the
attachment.

MORE INFORMATION
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This security feature provides an additional level of protection against malicious e-mail messages. Updates were available for earlier versions of Microsoft Outlook, but in Outlook 2002 this security feature is implemented by
default.

How to Customize Attachment Security Behavior
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You can modify the attachment security behavior in Outlook 2002 if you are using Outlook in one of the following scenarios:

- Outlook is run outside of an Exchange Server environment.

- In an Exchange Server environment, the administrator has not configured the Outlook Security settings to disallow changes to the attachment security behavior.

In these scenarios, modify the attachment security behavior by making a modification to the registry. Use the following steps to modify the registry.

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Use Registry Editor at your own risk.

1. Exit Outlook 2002, if running.

2. Click the Windows Start button, and then click Run.

3. In the Open box, type "regedit" (without the quotation marks), and then click OK.

4. Check to see if the following key exists. If it does, skip to step 5.

HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook\Security

If the key path does not exist, create the key path. To create the key path,navigate to and select the key:

HKEY_CURRENT_USER\Software\Microsoft

a. Click the Edit menu, click New, and then click Key.
b. Type "Office" (without the quotation marks) and press ENTER.
c. Click the Edit menu, click New, and then click Key.
d. Type "10.0" (without the quotation marks) and press ENTER.
e. Click the Edit menu, click New, and then click Key.
f. Type "Outlook" (without the quotation marks) and press ENTER.
g. Click the Edit menu, click New, and then click Key.
h. Type "Security" (without the quotation marks) and press ENTER.

5. Click the Edit menu, click New, and then click String Value.

6. Type the following name for the new value:

"Level1Remove" (without the quotation marks)

7. Press ENTER.

8. Right-click the new string value name, and then click Modify.

9. Type the extension of the file type that you would like to access with Outlook 2002 as follows:

"exe" (without the quotation marks)

To specify multiple file types, use the following format:

".exe;.com" (without the quotation marks)

10. When finished, click OK.

11. Exit the Registry Editor program.

When you start Outlook 2002, the file types specified in the Windows Registry are accessible.

NOTE: Microsoft recommends that only the necessary file types be enabled for access. If a particular file type is received rarely, it is recommended that Outlook 2002 be given temporary access to the file type in question and then
reconfigured to the blocked state by undoing the changes made to the Windows Registry.

Microsoft Exchange Server Environment:

If you run Outlook in an Exchange Server environment, your administrator can change the default attachment security behavior. For more information about how to configure Outlook 2002 in this environment, please see the Knowledge Base article:

Q290499 OL2002: Administrator Info About E-Mail Security Features

Attachment Behavior
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Attachments are divided into three groups based on their file extension, or type. Outlook handles each group in a specific way.

Level 1 ("Unsafe"):

The "unsafe" category represents any extension that may have script or code associated with it. Any attachment with an "unsafe" file extension is inaccessible if you use a version of Outlook that has the security patch applied
to it. The following list contains attachments that are considered unsafe:

File extension File type
---------------------------------------------------
.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
.vb VBScript file
.vbe VBScript Encoded script file
.vbs VBScript file
.wsc Windows Script Component
.wsf Windows Script file
.wsh Windows Script Host Settings file

The following list describes how Outlook functions when you receive an "unsafe" file attachment:

- Any "unsafe" attachment is not accessible. You cannot save, delete, open, print, or otherwise manipulate "unsafe" files. The top of the e-mail message indicates that Outlook has blocked access to the "unsafe" attachment; the attachment is not accessible from Outlook, however, the attachment is not actually removed from the e-mail message.

- If you forward an e-mail message with an "unsafe" attachment, the attachment is not included in the forwarded e-mail message.

- If you send an e-mail message that contains an "unsafe" attachment, you receive a warning message that says other Outlook recipients may not be able to access the attachment that you are trying to send. You can either disregard the warning message and send the e-mail message, or you can choose to not send the e-mail message.

- If you save or close an e-mail message that contains an "unsafe" attachment, you receive a warning message that says you will not be able to access the attachment from Outlook. You can override the warning message and save the
e-mail message.

- You cannot open objects that are inserted into Microsoft Outlook Rich Text messages by using the Insert Object command. You do see a visual representation of the object, but you cannot open or activate the object in the e-mail message.

- You cannot open "unsafe" files that have been directly stored in an Outlook or Exchange Server folder. Although these files are not attached to an Outlook item, they are still considered "unsafe." The following error message occurs in this situation:

Can't open the item. Outlook blocked access to this potentially unsafe item.

Level 2:

Level 2 files are not "unsafe" but they do require more security than other attachments. When you receive a Level 2 attachment, you are prompted to save the attachment to a disk; you cannot open the attachment from within the e-mail
message. By default, file extensions are not associated with this group, however, you can add file extensions to the Level 2 list.

NOTE: The list of files that are included in the Level 2 category can only be changed if you are using Outlook in a Microsoft Exchange Server environment and your mail is being delivered to an Exchange Server mailbox. These changes must be made by an administrator.

Other Attachments:

When you try to open an attachment other than those in the "unsafe" or Level 2 lists, you are prompted to either open the file directly or to save it to a disk. You can turn off future prompts for that extension if you click to clear the Always ask before opening this type of file check box.

NOTE: If a program associates itself with a new file extension, that file extension is treated as an "other" attachment until you add the file extension to the "unsafe" list. For example, if you install a program on your computer
that uses files with an .xyz file extension, whenever you open an attachment that has an .xyz file extension, the new program opens and runs the attachment.

By default, the .xyz file extension is not on the "unsafe" or Level 2 list, so it is treated as an "other" file extension. If you want attachments with the .xyz file extension to be treated as "unsafe," you must add the .xyz file extension to the list of "unsafe" file extensions.