Outlook 2011, like Entourage before it, keeps track of email addresses that you’ve recently sent messages to. Outlook can run into some problems with this, where the autofill will display addresses with your name but someone else’s address. This had been fixable in Entourage by using the method below:
Outlook 2011 either removed or moved the relevant button from the Compose preferences, but it looks like there’s two ways (one non-destructive, one possibly destructive) to clear recent addresses and contacts in Outlook.
When composing a message, a number of addresses are popping up. To clear the ones you don’t want from the Recent Addresses database, click the little gray “X” at the end of the line.
For any that don’t have an “X” in the name, here’s how to check the “Me” contact that may be storing those addresses and remove any that aren’t needed:
1. Click on Contacts in the lower-left corner of the Outlook window.
2. In Contacts, click the Organize tab
3. Click the button called Me.
The Me contact stores information about the Outlook’s default main user. If it has different information than your name, email, etc, these fields can be updated with your information.
Possibly destructive (not recommended):
There is another way to clear the whole Recent Address cache file, but it could cause data loss so I don’t recommend doing it. It will definitely trigger a database rebuild, which will take some time to run.
1. Quit Outlook
2. Locate this folder in your home folder:
~/Documents/Microsoft User Data/Office 2011 Identities/Main Identity/Data Records/Recent Addresses
3. Follow the sub-folders down until you come to a single file (should be named something similar to “x19_36260.olk14Recent”.) Move the file to the Trash.
4. Launch Outlook.
When you open Outlook, it will tell you that there’s a problem with the database and will tell you that a rebuild is needed. Select to rebuild the database.
Why I don’t recommend this: I tested both methods, and the rebuild of the database did not work. It finished successfully, but then Outlook would open, display an error then shut back down again. However, it does clear out everything in one shot so I’m including it. Maybe you’ll have better luck than me.