Simple hacks to manage the Outlook AutoComplete list

AutoComplete is one of the most underrated features of Outlook. Without even realizing, we extensively use AutoComplete list in Outlook to send mails every day. It saves the time by suggesting the most relevant email id to the partially entered address in To, Cc and Bcc sections of the send mail window; therefore you can avoid manually looking for a previously entered mail id or email address.

At the same time AutoComplete can also be unfruitful and may land you into troubles by suggesting a different sender or a misspelled email address. This doesn’t mean that you have to disable AutoComplete as a whole. This write-up is compiled to give a few useful pointers that help anyone master the art of maintaining AutoComplete list.

What benefits can you reap from regularly maintaining Outlook AutoComplete list?

  • The biggest advantage of AutoComplete feature is that your AutoComplete list will store up to 1000 entries in a system file with an extension “.NK2” called nickname list or nickname cache. Hence if you have sent mail to a recipient that does not exist in you contacts, there are chances that you might find the mail address in the auto complete list.
  • By managing your .NK2 file you can prioritize which suggestions to show up and which ones to be eliminated. This way you can make space for the important ones to come in future and can move Outlook data file to a new computer easily.
  • Additionally if you regularly monitor the .NK2 file by correcting it, the misspelled mail id’s that are stored in AutoComplete are eliminated; consequentially eradicating the chances of a wrong send.

How to efficiently use Outlook AutoComplete feature

Broadly speaking not all Outlook users would like to have AutoComplete list popping up while composing important mails. So lets begin by understanding how to enable or disable Autocomplete feature in Outlook.

  • How to disable or enable AutoComplete in Outlook1.Select Options from File menu in Outlook
    2. Choose the Mail tab on the left side of the window
    3. Under Send messages find the option named Use Auto-Complete List to suggest names when typing in the To, Cc and Bcc and check the box to enable AutoComplete.enable or disable autocomplete4. Uncheck the box to disable AutoComplete.
  • Rollback from recent people feature to old format of AutoCompleteWith the update in 2017, AutoComplete took the form of Recent People section which shows up five results as suggestions with pictures. Apart from better visual experience this feature makes the whole experience of auto fill a bit cumbersome. With only five suggestions, greater portion of the contact information is to be typed in to find the exact one needed. On the other hand the old format of AutoComplete list populates up to fifty easy to find results.Note: Before you follow the below mentioned procedure create a restore point or backup registry, just to be cautious.Here’s how to roll back from recent people in Outlook
    1. Type regedit in search bar and select Run as administrator as shown belowrun regedit as admin2. Copy the below path and paste it in the text box just below the file tab as shown in the picture below and hit enter.HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Optionsregedit path3. Now, on the right half of the screen, double click on the DisableAutoCompletUpdate and change the Dword: Value to 1.This will revert the changes done by the Outlook update and bring back the old AutoComplete list.
  • Clear the existing Autocomplete listWhen you start working with a new department or organization you would no longer need a lot of entries that exist in the current list. The best course of action in this situation would be to clear all the entries. Note: But before you clear the AutoComplete list export Outlook contacts to new computer or version to account for all the unsaved contacts existing in the list.You can also choose to remove them one by one individually which will be talked about in the below sections or choose to clear the entire list according your discretion. This subsection only talks about clearing the whole AutoComplete list.How to clear AutoComplete list
    1. Go to File and select Options
    Select Mail from the left side of the window
    3. Under Send messages click on Empty Auto-Complete List.

empty autocomplete


  • Refine your Auto-Complete to efficiently manage the entriesTo work as designed Auto-Complete does not only save the valid email addresses. All the misspelled or incomplete entries are also added to list.
    You may also have a few items in the list that you no longer need, from the .NK2 file make use of the below steps to remove specific entries in the AutoComplete list.1. Type in the alphabet or name that return the suggestion you want to remove.
    2. As you move your cursor over the suggestion you would want to remove, click on the X to delete the suggestion from the list.
    3. This will remove the email address form the AutoComplete list only and not from contacts.
  • Increase or the Capacity of your AutoComplete listAs mentioned above the number of entries is limited to one thousand in every Outlook version except for Outlook 2007 which is two thousand.
    Using this method below, you can increase the limit to your desired number. However it is not a recommended method as it is might increase the chances of nickname cache getting corrupted and it is also untested.
    If you still would like to increase the number of entries despite the risk involved, make sure you have a backup of the registry as a precaution.1. Press windows button on the keypad and type in “Regedit” and select the suggested run command.
    2.Go to the following registry path using the subkey:
    HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoNameCheckNote: The value 16.0 in above path should be replaced by 15.0 for Outlook 2013, 14.0 for Outlook 2010, 12.0 for Outlook 2007, and 11.0 for Outlook 2003 respectively.
    3. Go to the edit menu, click on new and then click on DWORD value.
    4. Enter the text MaxNickNames and hit enter.
    5. Now select Modify from the edit menu and enter the desired value of the limit.
    6. Exit registry editor.
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Tony Landry

Tony Landry is a Web Content Editor at Remo Software. He loves to write, edit, and manage content for users trying to troubleshoot and fix problems on Windows, Outlook, storage drives, and Cloud storage networks. With an aptitude that transcends writing, Tony is recognized as a Microsoft Outlook, Word, and PowerPoint expert. His comprehensive solutions stem from an in-depth understanding of these tools, enhancing his standing as a trusted problem-solving resource.

He has published more than 200 articles on the Remo Software blog. He actively engages in research and problem-solving techniques to consistently generate great web content. Fixing various hardware problems on computer and storage devices along with a great knack for fixing Outlook errors, Tony is also the fun-time IT guy for all his work friends. Tony Landry’s work has been published in windowstechit, onlinegeeks, journeybytes and onlinecomputertips.

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