Outlook provides options to configure auto save functionality. It allows you to choose the folder where you want to store the auto save items and it also allows the users to specify the time period after which the messages needs to saved automatically. Listed below are instructions to enable automatically save messages feature in Outlook 2013, Outlook 2010 and Outlook 2007
Enable auto save messages in Outlook 2013 and Outlook 2010
Click on the File menu –> Options link, navigate to Mail tab available on the left hand side. Scroll down to Save messages section.
In Save messages section, mark the check box with label as Automatically save items that have not been sent after this many minutes. And specify the minutes after which you want the save messages.
You can specify the folder where you want these messages using the Save to this folder dropdown field. Click OK button to apply and save these changes.
Enable auto save messages in Outlook 2007
In Outlook 2007, automatically save messages can be enabled using E-mail Options.
To Access Save Messages options, Click on Tools menu –> E-mail options
In the Email-Options window, click on the Advanced Email Options button, this would display the following window
Specify the folder where you want to save the auto save message by selecting a value in the AutoSave items drop down. The list of available values are Drafts, Inbox, Sent Mail and Outbox
Using AutoSave items every: field, you can specify the time in minutes after which Outlook will automatically save the messages.