The drop-down list of names that Outlook gives us to auto-complete a name or address being written is stored in a file called <ProfileName>.NK2 in our Application Data\Microsoft\Outlook directory. This file is stored in a proprietary binary format, and there's no known documentation for it as far as I know. There seems to be a company that (apparently) reverse-engineered the format and are selling a cache-editing tool, but it's pricey - the basic desktop version can edit, import/export and print for $35. The network/helpdesk editions can do remote NK2 editing for all computer on the network, but gets really pricy with per-seat licenses and so forth.
(They're called Ingressor, if anyone needs those tools)

It turns out, however, that the most common usage for such an editor isn't necessary. If we just want to remove an item from the cache we can do it from within Outlook itself - simply navigate the drop-down options using the arrow keys and press Del on the one we want to erase - and away it goes.

Very simple, and even logical when you think about it. We're just not used to live editing of an auto-complete list.

8 Comments

• Karstan said Friday, September 1, 2006 6:12:21 PM

  How to transfer/copy my autocomplete cache to a new computer please email what you can find

• AvnerK said Friday, September 1, 2006 6:20:46 PM

  I haven't tried it, but I would assume that copying the .NK2 file in the user profile folder to a new computer will copy the autocomplete cache. Stands to reason.

• Antoinette McPherson said Wednesday, October 3, 2007 5:37:47 PM

  Thank you for this help. It is really a logical and simple fix... which I could not figure out! GREAT!

• randy revilloza said Wednesday, May 14, 2008 3:36:19 PM

  I want to erase my name or unpublish it on the net.

• Amr Bahi El-Deen said Monday, August 24, 2009 6:30:22 PM

  Thanks for that Information man. It's really helpful :-)

• FlowerBeauty said Monday, November 30, 2009 12:37:15 AM

  Здрасьте. Прошу у Вас совета. У меня сложилась очень неприятная ситуация. Дело в том, что мой блог с недавнего времени перестал показываться в результатах поиска Yandex'a. Сам блог проиндексирован, то есть если посмотреть наличие конкретной страницы в результатах поиска, то она там имеется. А вот по поисковым запросам, да и по точным текстовым вхождениям сайт не находится. При чём его нет не только в 100, но даже в тысяче показов. Ума не приложу, что случилось. Сайт был доступен, перебоев на хостинге не было. А обнаружил это - по счётчику ЛивИнтернет, который вдруг стал показывать гораздо меньшее количество посещений. Кстати, читатели с Гугла и Рамблера идут в прежних объёмах.

• Acinnina said Saturday, February 27, 2010 3:46:49 AM

  итак: мне понравилось! а82ч

• Amatures Salinas California said Thursday, March 4, 2010 11:20:30 AM

  well.. it's like I said!