See Suggested Contacts and Auto-Complete Lists to learn more about Outlook 2010's autocomplete cache and suggested contacts.Outlook 2010 also creates a contact for people you send mail to, as insurance if the autocomplete cache becomes corrupt.When you import the NK2, the contents of the file are merged into the existing nickname cache that is currently stored in your mailbox.The .nk2 file is renamed with a file name extension on the first start of Outlook 2010.The nickname files (.nk2) used by Outlook 2007 (and 2003) is found at If the users are losing addresses of people they recently replied to (but not older addresses), it's because Outlook crashes or does not close properly and the changes are not written to the NK2 file. Less used addresses are replaced by new addresses when the NK2 contains 1000 addresses in Outlook 2003 or 2000 address if using Outlook 2007.If all addresses disappear, it means something is corrupt and Outlook is replacing the NK2 with a new, clean one. EXE continues running after you exit Outlook If you're using the autocomplete cache as your address book because it's too much effort to right click on an address and save it as a new Contact, you should use a utility that creates contacts from all addresses you reply to, as the autocomplete cache is not a good substitute for contacts.
Beginning with Outlook 2010, Outlook does not use the NK2 file; it stores the autocomplete cache in the mailbox or data file and caches the addresses in an autocomplete stream at .Outlook 2003 Outlook 2007 Outlook 2010 To learn more about the files Outlook uses and where they are stored, visit Outlook & Exchange/Windows Messaging Backup and Dual-Boot. The Outlook 2010 Auto-Complete suggestions/cache functions just like it did in Outlook 2007, and just like before, we’re going to show you how to disable it. NK2 file you need to mess with like back in the Outlook 2003 / Outlook 2007 days. The limit can be raised in Outlook by use of a registry setting.Note: this value will not exist by default and is only needed if you want to change the limit.
You'll need to rename it so it matches the name of your new profile.