How to Unblock Attachments in Microsoft Outlook

1. Run Regedit, and go to this key:
   
   HKEY_CURRENT_USERSoftwareMicrosoftOffice10.0OutlookSecurity (change 10.0 to 9.0 for Outlook 2000 SP3 or to 11.0 for Outlook 2003)
2. Under that key, add a new string value named Level1Remove.
3. For the value for Level1Remove, enter a semicolon-delimited list of file extensions. For example, entering this:
   
   .mdb;.url
   
   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.