Outlook provides a cache of email addresses as you use them in new email messages. This cache, sometimes called a nickname cache, is intended to improve user productivity. As you type an address in an email address field, Outlook lists possible addresses matching the letters you’ve entered. Figure 1 shows an example of this feature.
Outlook 2010 changes the location of the AutoComplete Cache. It’s no longer an .nk2 file but is now a hidden folder within an Exchange Mailbox or a .pst file, depending on the account type in Outlook. The principle is the same, of course; however, with the nickname cache in the mailbox, the content now travels with the user. When you recreate a user’s profile on another workstation, their nickname cache is unaffected.
Outlook 2010 also adds a folder to Contacts labeled Suggested Contacts. Addresses get added to this folder as you send or reply to messages addressed to recipients who don’t already exist in your address book (aka your Contacts folder). That sounds very simliar to the AutoComplete process! AutoComplete is a productivity enhancement that shows an address as you start to type a common recipient address so you can select the address instead of typing it. Suggested Contacts are addresses that you might consider adding to your Contacts, and Outlook makes it easier to do so. You can double-click an entry in Suggested Contacts and a Contact Form opens that allows you to fill in more information and then save it to your Contacts Folder. Figure 2 shows the Suggested Contact folder with a few recently used recipients.
Suggested Contacts is a way for administrators and users to control AutoComplete cache contents directly through the Outlook interface.
Addresses added to Suggested Contacts are used for AutoComplete and addresses entered as recipients of email messages that do not reside in the user’s Contacts folder are added to Suggested Contacts.
You can copy and paste contacts from a contacts folder to Suggested Contacts to add their addresses to your AutoComplete cache.