Auto-Reply for all messages without subject
To create a rule, follow next steps:
1. Create a template with text which you want to send like Auto-Reply. See Using templates to facilitate more versatile E-mail Distribution for more details.
2. Select Tools -> Rules and Alerts... to display the Rules and Alerts dialog box.
3. In the Rules and Alerts dialog box, choose New Rule...:

4. Choose the Start from a blank rule option and then the Check messages when they arrive option, click Next.

5. Choose conditions:
- If you want to limit the list of people who send you messages, choose one or several conditions:
- from people or distribution list and click people or distribution list in the Step 2 text box to
choose them:
- which has an attachment
- sender is in specified Address Book and click specified in the Step 2 text box to choose the Address Book.
- from people or distribution list and click people or distribution list in the Step 2 text box to
choose them:
- If you want to use this rule for all incoming messages, click the Next button. Click
Yes in the information dialog box:
6. Choose reply using a specific template in Step 1, then click a specific template in Step 2 and choose the template:
- In the Select a Reply Template dialog box, on the Look In list box, choose User
Templates in File System:
- Click the Browse button and choose the path to your template in the Browse For Folder dialog box.
- In the Select a Reply Template dialog box, choose the template and then click Open.
When you choose a template, click Next.
7. Choose exceptions: select except if the subject contains specific words and click specific words in the Step 2 text box. You have to insert numbers and letters (or at least all vowel letters, because any phrase or word in the subject consists not less than one vowel letter):

8. Click Next again, name your rule, and click Finish.
Note: For some rules it is necessary to restart Outlook.