Added 6/25/07: Given the popularity of my post I must put a word of caution. Allowing executable extensions give you more freedom but less security (I've seen viruses pass AVs before). I would recommend allowing unsafe attachments just for a specific email, and undoing it after downloading the attachments. Of course make sure the email is from a trusted source and still treat it as if it's a virus by default (i.e. scan it, look for patterns in the email body, etc).
I'm sure you've seen before "Outlook blocked access to the following potentially unsafe attachments: xxx.exe":
I found there's very little documentation out there on how to lower the security level or allow a file a know source sent you. You'll find below the registry hack to allow specific file types Outlook blocks by default. There's also a kb article about it and as the article mentions make sure you backup your registry before you start editing it.
Run -> regedit and go to :
HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\Security
-
Backup:
- Add a new String Value called: Level1Remove
- Edit it and save the value data to the extension you wish to allow (add a semi-colon delimiter for multiple extensions).
Ex: .bat or .bat;.exe;.scr
- Restart outlook (no need to restart your computer) !