Outlook blocks EXE and MDB file attachments (and others)

1. Close Outlook
   Open the Registry Editor
   
2. Office XP/2002 : HKEY_CURRENT_USER\ Software\ Microsoft\ Office\ 10.0\ Outlook\ Security
   Office 2003: HKEY_CURRENT_USER\ Software\ Microsoft\ Office\ 11.0\ Outlook\ Security
   
3. Create a new string value by selecting New and then String Value from the Edit menu.
   
4. Name the new value Level1Remove.
   
5. Double-click the new Level1Remove to edit it, and enter the filename extensions you'd like to stop Outlook from blocking. Extensions should be typed in lower case, without the dots (.), and separated by semicolons (;). For example, type
   exe;mdb;vbs to allow .exe, .mdb, and .vbs attachments, respectfully.
   
6. Click Ok and then close the Registry Editor when you're done.
   
7. The next time you restart Outlook, you'll now be able to open previously-blocked attachments.