Mac Outlook NK2 File

Mac Outlook NK2 File

Previously I wrote an article, located here, about the NK2 file on Windows that stores the email addresses you type into the “To Field” when sending emails. The NK2 file stores the history of what you type or paste into the To field so it can auto complete for you in the future. This is a great feature however deleting old entries is not always the easiest and that makes it a bit unfortunate. You can typically turn off auto complete however you could also modify the files that store the contact cache that is used for auto complete. Follow the directions below to locate email addresses stored in the To Field Outlook for Mac cache to either modify or delete.

Remove Email Addresses From To Field Auto Complete Cache On Outlook For Mac 2011:

**Please note this is not the correct way to complete the below task however I was unable to find a olk14Contact file editor. Proceed with caution and make sure to backup anything before it is modified or deleted.

I am guessing this also works for previous versions of Outlook for Mac however I cannot confirm that since I have the latest version already installed. On Mac OSX Lion it is a bit different removing addresses from the auto complete cache because they are not always stored in one file but the good news is they are stored within a specific directory structure so we can issue a few simple commands to locate the email addresses located in the To Field cache and then delete the same email addresses that are used for auto complete in Outlook for Mac 2011.

First open a Terminal window and issue the below command to navigate to the To Field auto complete cache.

Outlook For Mac 2011 Auto Complete Cache Location:


  1. cd /Users/alex/Documents/Microsoft\\ User\\ Data/Office\\ 2011\\ Identities/Main\\ Identity/Data\\ Records/Contacts/

I would first backup the entire Contacts directory in case something goes wrong. You can do this by issuing the below commands.

Backup Entire Outlook Contact Directory & Contact Database:


  1. cd ../
  2. cp -pR Contacts Contacts.DATE-HERE
  3. cd Contacts/

In the above command replace YOUR-USERNAME-HERE with your login used on the Mac where you want to delete an email the To Field auto complete cache. Once in the Contacts directory I am not 100% sure if the sub directories will be the same name however the idea will be the same. So first what we are going to do is issue another command that will recursively search every sub directory and its contents for the email address in question.

Recursively Search Outlook For Mac Email Address Auto Complete Sub Directories:


  1. host:Contacts alex$ grep -r *
  2. Binary file 0T/0B/0M/1K/x01_1606.olk14Contact matches
  3. host:Contacts alex$

You will replace with the email address you want to remove from the email address auto complete cache. As you can see it states that some file with the ending of .olk14Contact contains the file. It is also possible that the file is named something like x19_4.olk14Recent or a file with the ending .olk14Recent contains the file. In my experience it is either .olk14Recent or .olk14Contact and at some point I believe the .olk14Recent becomes separate .olk14Contact files. I suggest you remove the entire contact file which in this example is x01_1606.olk14Contact. You could attempt to edit the file however I have not had success with editing and didn’t have the time to continue different methods so you are on your own there. If anyone has details for editing please post in the comments and I will update the article.

Below I do show the format of a olk14Contact file just so you can match the format of the file you are going to remove.

Outlook For Mac 2011 Email Auto Complete Cache Contact File:


  1. CTRC^@^@^HF^@^@^HF3ß·s^@^@^FF^@^^^@^@^@^@^@ü^@^@^GJ^@^@^Be^@^@^@^D^@^@^B^@^@^@^B^@^@^C^A^@^@^@^D^@^@^Cd^@^@^@^D^@^@^C^@^@^@^D^@^@^Cä^@^@^@^D^@^@^Cè^@^@^@^D^@^@^Cé^@^@^@^D^@^@^Cú^@^@^@^D^@^@^G^@^@^@^H^@^@^Ká^@^@^@^A^@^@^Kâ^@^@^@^A^@^@^Me^@^@^DÂ^@^@^]f^@^@^@^X^@^@^]g^@^@^@^R^@^@^_^A^@^@^@^P^@^@^_^B^@^@^@^F^@^@^_^D^@^@^@^H^@^@^_^F^@^@^@$^@^@^_^G^@^@^@^T^@^@^_^H^@^@^@^D^@^@^_      ^@^@^@
  2. ^@^@^_^K^@^@^@"^@^@^_!^@^@^@"^@^@^_K^@^@^@"^@^@ ^@^@^@^@^D^@^@ ^A^@^@^@^H^@^@ ^T^@^@^@^H^@^@ ^U^@^@^AD^@^@H^@^@^@^@^P^@^@^]f^@^@^@^@^@^N^@^@^@^B^@^@^@^@^@^@^@^F^@^@^FKTIFF^@^@^@^@^@^@^@^@ÊÙúø^A^@<!--?xml version="1.0" encoding="UTF-8"?-->
  4.         OutlookCellPhoneUuid
  5.         Outlook{CAAAAA41-E300-42D9-5DDD-0AE5AAAA931B}
  6.         OutlookEmailUuids
  9.                 Outlook{29BAB71D-1D06-429A-9897-A101F6DD3111}
  11.                 Outlook{F51BF2C1-A916-4A8C-9D53-A25C06FCAC6C}
  13.         OutlookHomeAddressUuid
  14.         Outlook{AAAAA7D5-FBBC-470B-AA94-F2AAAAA008E9}
  15.         OutlookHomePhoneUuid
  16.         Outlook{C0AAAAEE-AAAA-41CF-AAA8-04AAAAA9CDD7}
  17. Field
  21. Address
  23. Number
  25. Name
  27. Address
  31.         groupUuids
  33.         syncServicesContactUuid
  34.         Outlook{2CAAAA92-7A58-AAAA-BAAD-30AAAAA20588A}
  36.^@A^@m^@a^@s^@e^@t^@t^@a^@K^@a^@h^@w^@i^@f^@e^@2^@1^@3^@0^@ ^@M^@a^@r^@y^@l^@a^@n^@d^@ ^@A^@v^@e^@.^@L^@o^@u^@i^@s^@v^@i^@l^@l^@e^@K^@Y^@4^@0^@2^@0^@5^@+^@1^@ ^@(^@5^@0^@2^@)^@ ^@4^@5^@8^@-^@4^@1^@7^@4^@+^@1^@ ^@(^@5^@0^@2^@)^@ ^@3^@8^@6^@-^@6^@5^@2^@1^@F^@r^@i^@,^@ ^@A^@p^@r^@ ^@1^@5^@,^@ ^@1^@9^@7^@7^@^@^@^@^@^@E^@^@^@^@^@^@^@^@^@^@^G^@^@^Be^@^@^@^@^@^@^@^D^@^@^B^@^@^@^@^@^@^@^D^@^@^C^A^@^@^@^@^@^@^@^A^@^@^Cd^@^@^@^@^@^@^@^D^@^@^C^@^@^@^@^@^@^@^A^@^@^Cä^@^@^@^@^@^@^@^D^@^@^Cè^@^@^@^@^@^@^@^B^@^@^Cé^@^@^@^@^@^@^@^D^@^@^Cú^@^@^@^@^@^@^@^A^@^@^Ká^@^@^@^@^@^@^@^B^@^@^Kâ^@^@^@^@^@^@^@^A^@^@^Me^@^@^@^@^@^@^@^G^@^@^]f^@^@^@^@^@^@^@^D^@^@^]g^@^@^@^@^@^@^@^D^@^@^_^A^@^@^@^@^@^@^@^D^@^@^_^B^@^@^@^@^@^@^@^D^@^@^_^D^@^@^@^@^@^@^@^D^@^@^_^F^@^@^@^@^@^@^@^D^@^@^_^G^@^@^@^@^@^@^@^D^@^@^_^H^@^@^@^@^@^@^@^D^@^@^_     ^@^@^@^@^@^@^@^D^@^@^_^K^@^@^@^@^@^@^@^D^@^@^_^O^@^@^@^@^@^@^@^C^@^@^_^]^@^@^@^@^@^@^@^C^@^@^_!^@^@^@^@^@^@^@^D^@^@^_K^@^@^@^@^@^@^@^D^@^@H^@^@^@^@^@^@^@^@^A^Häã¢O`«MàdÌ3ú

Once removed you must restart (make sure to remove all contacts before restarting so you only have to rebuild the database once) Outlook before the changes take effect however when you restart Outlook it will freak out and require a rebuild of the Outlook Contacts database. This takes a little while to rebuild so relax while it does so. During the rebuild process you will see the process move forward similar to the below examples of rebuilding the Outlook database on Outlook for Mac 2011.

Microsoft Database Utility Launch: Main Identity Rebuild

Microsoft Database Utility Rebuilding Main Identity

Microsoft Database Utility Main Identity: Scanning

Microsoft Database Utility Rebuilding Main Identity: Scanning

Microsoft Database Utility Main Identity: Copying To A New Database

Microsoft Database Utility Copying Results To A New Database

Microsoft Database Utility: Select An Identity – Main Identity

Microsoft Database Utility: Select An Identity

Once the database has been removed you can start Outlook and the previous email address that was located in the auto complete To field will no longer be present.

Microsoft Outlook for Mac 2011 Step by Step (Paperback)

List Price: $29.99 USD
New From: $12.98 USD In Stock
Used from: $0.01 USD In Stock

Outlook for Mac 2011 Essential Training (CD-ROM)

New From: $49.00 USD In Stock
Used from: Out of Stock