Size limit of Outlook AutoComplete file (.NK2)

By default, MS-Outlook limits the number of records that are allowed to be added into the AutoComplete (nk2) file.
For Outlook 2003 - The maximum number of AutoComplete records is 1000.
For Outlook 2007 and Outlook 2010 - The maximum number of AutoComplete records is 2000.

If you want to modify the maximum records limit, you can do it by adding a new key and value into the Registry key of Outlook.
For Outlook 2003, The maximum records value is located in the following key/value:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\AutoNameCheck]
"MaxNicknames"=dword:000003e8
In the above example, the MaxNicknames value is set to 0x3e8 (1000 records), but you can increase or decrease it to any value you want. In order to easily add this key, simply select above Registry text, copy it to the clipboard, paste it into a text editor, and then save it as Unicode file with .reg extension. The created .reg file can be used to easily import this Registry key/value into the Registry.


For Outlook 2007, The maximum limit value is located in the following Registry key/value:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\AutoNameCheck]
"MaxNicknames"=dword:000003e8


For Outlook 2010, The maximum limit value is located in the following Registry key/value:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\AutoNameCheck]
"MaxNicknames"=dword:000003e8

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