.NK2 file is storing email address history which has been send. It is good that you backup and migrate the .NK2 file when rebuild, replace or swap the device. User will not notice the change and it’s a plus for your daily operation.

• For  Windows XP

C:\Documents and Settings\%UserName%\Application Data\Microsoft\Outlook

• For Windows 7

C:\Users\%UserName%\AppData\Roaming\Microsoft\Outlook

robocopy “Source” “Destination” /E /R:n

Syntax:

Source  |  Source Directory

Destination  |  Destination Location

Switch:

/E  |  Copy sub-directories, including Empty Folder

/R:n  |  Number of Retries on failed copies: n = numbers of loop