How to clear the AutoComplete list in Outlook 2010

Outlook 2010 introduced a change to the way the AutoComplete list (aka: nickname cache) is stored on the client.  The new Roaming AutoComplete list is now stored on the Exchange Server. A user’s recipient AutoComplete list is now available to any computer on which Outlook 2010 runs that is connected to the same Exchange account. Individual names can be easily removed from the list by using the new inline Delete function.  Just simply type the first few characters of the name you wish to delete and press the Delete key or click the X.


What this means for you is that your AutoComplete list is synchronized between platforms: OWA, Windows Mobile and Outlook will all share the same AutoComplete list.  While this sounds up front like a great enhancement there are some changes that you need to be aware of in case you need to clear this list.

First, there is no more NK2 file.  The actual file you are looking for is located is:


Deleting this file will not clear your AutoComplete list.  As soon as you start Outlook 2010 the file will reappear, along with any bad addresses.  So how does one clear the entire list?

Use one of the methods listed below to reset the Outlook nickname cache for Microsoft Outlook 2010.

Method 1

  1. With Outlook 2010 open, click File (BackStage), and then click Options.
  2. Click the Mail tab.
  3. Under Send Messages, click Empty Auto-Complete List.

Outlook will generate a new nickname cache.

Method 2

  1. Click Start, and then click Run.
  2. Start Outlook by using the /CleanAutoCompleteCache switch.
    For example: Outlook.exe /CleanAutoCompleteCache
    Note If Outlook is not installed in the default location, you will need to point to the path of Outlook.exe.

Outlook will generate a new nickname cache.

Reference KB287623 for more information…

Published by Wouter Makkinje

I am a 30 Year old IT Consultant from Kalmar Sweden.

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