Outlook Autocomplete Name List (outlook.NK2)
If you just switched office computers and you’re wondering why the TO box in Outlook doesn’t autocomplete your co-workers email address like your old computer did then what you have encountered is a missing Outlook.NK2 file. The Outlook.NK2 file is a cached list of all email addresses that you have sent to for future autocomplete use.
If you still have the old computer then you can simply copy offer that nk2 file to the new machine. Here is the file path:
C:\Documents and Settings\user\Application Data\Microsoft\Outlook\Outlook.NK2
The filename may also be the name of the user account but still has the .NK2 file extension.
These files may also become corrupted (like anything microsoft). If that is the case then you can try to recover the data with a utility like NK2View.