You can turn off the server-side Junk Email Filtering for your mailbox.
- Log in to your Exchange mailbox via OWA.
- Navigate to Options and turn off automatic Junk Email filtering. Depending on your Exchange version,
- Save changes.
You can also disable the built-in Junk E-mail Filtering in Outlook:
- Outlook 2010/2013:
- Outlook 2007:
Now none of your messages will be moved to the Junk E-Mail folder automatically, i.e. all emails will be delivered to Inbox regardless of the Spam score.