Knowledge Base

How to migrate your autocomplete cache


You would like to migrate the autocomplete cache from your old Outlook to a newer version of the software.


Microsoft Outlook is equipped with a mechanism that helps you fill the To, Cc and Bcc fields by suggesting recipients to whom you wrote previously. The autocomplete information (also known as the Outlook Auto-Complete list or nickname cache) is stored either in a local cache file (in older Outlook versions) or inside the content of your inbox. However, this data is not included when you migrate your mailboxes using CodeTwo migration software (see the Related products section below this article). There are two ways to move the autocomplete cache to your new environment, depending on the version of your older Outlook.

In Outlook 2007 or older

In the older versions of Outlook, the autocomplete cache is stored in the .nk2 file located in the following directory:


To migrate the autocomplete cache, you have to access the folder above and copy the.nk2 file to the same location on a machine with a newer Outlook version installed. Once this is complete, run the Outlook on the new machine with a special flag to force the application to import the data from the .nk2 file:

  1. Press Windows + R.
  2. Type the following command:
    outlook /importnk2
  3. Press Enter.

Outlook should recognize the file and import your autocomplete information. If you need more detailed instructions, see this MS article.

In Outlook 2010 or newer

In the newer Outlook versions (starting from Outlook 2010), the entire autocomplete cache is kept as a single, hidden message located in your Inbox folder. Therefore, to move this data to a machine with a more recent Outlook version, you have to export that message from your old Outlook and import it into the new version of the software. This cannot be done within Outlook itself, so you will need to use a tool called MFCMAPI

The whole procedure is described in detail in this MS article (see the section: How to copy the AutoComplete list / Outlook 2010, Outlook 2013, and Outlook 2016).

In a nutshell, after you log in using MFCMAPI you have to find and open your Inbox (located under Root Container, Top of Information Store / IPM_SUBTREE). There should be a message with the subject IPM.Configuration.Autocomplete. Export that message and copy the .msg file to the computer with the newer Outlook. After that, open MFCMAPI on the new machine and import the previously exported message to the Inbox folder.

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