A profile contains configuration information for email accounts, data files, and information about where your email items are saved. When Outlook runs for the first time, a profile is created automatically and is named Outlook. As you add or change email accounts, or include an additional Outlook Data File (.pst), the profile is updated.
Outlook profiles are stored in the Windows registry and contain the following information:
What account information to use This information includes the user name, display name, email server name, and Internet service provider (ISP) account password.
Where the email data is delivered and saved In Outlook, data is delivered and saved either on the email server or in an Outlook Data File (.pst) file on your computer. Some accounts, such as Microsoft Exchange Server accounts might use an offline Outlook Data File (.ost).This data includes rules, messages, contacts, calendars, notes, tasks, journals, Search Folders, and other settings.
Most people need only a single profile. Outlook makes it easy to use a unique Outlook Data File (.pst) for each email account. If you previously used multiple profiles to keep accounts isolated — such as work and home accounts, you might want to consider using a single profile. Also, starting with Outlook 2010, multiple Exchange Server accounts can be used in one profile.
Using a profile doesn't prevent other people who use the same computer from accessing your Outlook information. If you share your computer with another person, we recommend that you create a Windows user account that uses a password for each person. Each person who then uses Outlook will have a unique profile.