
Cause:
Can be either of 2 things below
1. The function is turned off. (Tools > Options > E-mails Options > Advanced E-mail Options > Suggest names while completing To, Cc and Bcc fields (must be checked to be on)
2.The history is stored in .NK2 files in the users profile. Name is same as the name on the users profile. When creating a new mailprofile, this information gets replaced with a new file.
Location on Windows 7: C:\Users\-YOUR USERNAME-\AppData\Roaming\Microsoft\Outlook
Location on Windows Xp: C:\Documents and Settings\-YOUR USERNAME-\Application Data\Microsoft\Outlook
Solution 2: Close Outlook if it's not closed already. Rename the new file to something like .old at the end or something. Then rename the old NK2-file to the same name as the new file. Then start Outlook and all history should be restored.