Cause: This is intentional, in order to make your computer more secure.
Solution: Outlook 2002, Outlook 2003 and Outlook 2000 SP3 allow you to use a registry key to open up access to blocked attachments. Always make a backup before editing the registry. Open the Registry Editor, 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 semicolondelimited list of file extensions. For example, entering “.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 no space between extensions.
If you prefer not to edit the Registry, you can use one of these tools to make the change; not all support both Outlook 2002 and 2000.
(http://www.slovaktech.com/attachmentoptions.htm): This is a shareware COM add-in that adds an Attachment Security Options page to the Tools > Options dialog in Outlook 2002 to allow you to manage which file attachments are blocked. It is only for Outlook 2000 SP3, Outlook 2002, and Outlook 2003. It also provides a user interface for setting two other Outlook options: Read As Plain Text (Outlook 2002, SP-1 or later) and Minimize to System Tray.
Attachments Zip Compressor
(http://slipstick.com/redirect.asp?id=compressor): Automatically compresses outgoing attachments into .zip files. Can extract files from incoming .zip attachments or compress attachments in an incoming message. Can handle incoming files that Outlook blocks and put them into .zip files.
(http://mcdev.com/programs.php?page=DetachOL): A free, standalone utility to change the list of blocked file attachments according to the level of risk you’re willing to take. Works with Outlook 2000, 2002, and 2003.
Outlook Permissions Add-in (www.mrhtech.com/Software /OPA/): A freeware add-in for adjusting which attachments you can open under Outlook’s increased security, for Outlok 2003, 2002 and Outlook 2000 SP3 or later.
Modifies the Windows Registry to change the list of blocked file attachments according to the level of risk you’re willing to take, always show the Bcc field, minimise Outlook 2002 to the system tray, and disable or enable MSN Messenger. It is freeware, and is available for Outlook 2002 and Outlook 2003.
Xenos Outlook Security Extension
(www.xenossoftware.com/ xsoutlooksecurityext/): A utility to manage file attachment blocking in Outlook 2000 SP3, Outlook 2002, and later. Also manages optional settings such as minimize to tray and purge data file on exit. New settings added in new Outlook updates are supported through online updates to the software.
After applying this registry fix or using one of the above tools, the user still has to save the attached file to a system drive before opening it.