This article was previously published under Q259514
Microsoft Outlook 2000 Service Release 1 (SR-1) provides an attachment security feature that is designed to increase the security protection for certain types of e-mail attachments. This feature provides explicit warning language when attachments are opened, and you are required to save the attachment to the file system before opening it. This can help you avoid accidentally releasing viruses that hide in certain file types.
Note: In previous versions of Outlook, this functionality was provided in three separate patches: one for each version of Outlook.
When you open attachments with file name extensions such as .exe, .bat, .com, or .cmd, you receive the following warning message:
Attachment Security Warning
The file may contain a virus that can be harmful to yourcomputer. It is important to be VERY certain that this file issafe before you open it. You must save this file to disk beforeit can be opened.
Filename: "file name" Type: "file type"
To save the attachment, click Save to Disk.
Caution: The attachment warning runs for all attachments with executable file name extensions. It does not detect, or clean a virus from an infected attachment. If you save a file that has a virus, and then run it from the hard disk, your computer is still infected. Saving the file is simply an extra precaution to take when considering the safety of the attached file. You must still use an updated virus-scanning program to check the file for a possible virus.
Microsoft Office files, such as .doc, .xls, or .ppt, are not affected by this patch, and behave just as they did before installing the patch. To control macro behavior for Office documents, set the security level in the individual Office program itself.
To Modify the Behavior of the Attachment Security Warning
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756 How to back up and restore the registry in Windows
To either add, or remove file types for the Attachment Security Warning, follow these steps:
Click Start, click Run, type regedit, and then click OK.
If the Security key is not present, right-click the Outlook key, point to New on the shortcut menu, and then click Key. Type Security as the name, and then press ENTER.
Click to select the Security key, and on the Edit menu, point to New. Click String Value, type AddWarningFileTypes, and then press ENTER.
Right click AddWarningFileTypes, and then click Modify. Enter the extensions of those file types for which you want to receive a warning in the Value data box. Note that the file extensions should be entered as semicolon- (;) delimited strings without using any periods (.).
Click the Security key, on the Edit menu, point to New, and then click String Value. Type RemoveWarningFileTypes, and then press ENTER.
Right-click the RemoveWarningFileTypes value, and then click Modify on the shortcut menu. Enter the extensions of those file types for which you do not want to receive a warning. Note that the file extensions should be entered as semicolon-delimited strings without using any periods.
Quit Registry Editor.NOTE: You must have some string value added to the AddWarningFileTypes key in order for RemoveWarningFileTypes to work. If necessary create a fake extension for AddWarningFileTypes, such as <qqq>
For additional information about this feature as used in previous versions of Outlook, click the article number below to view the article in the Microsoft Knowledge Base: