Determine the Outlook Data File (.pst) format

Beginning with Microsoft Office Outlook 2003, a new Outlook Data File (.pst) (Outlook Data File (.pst): Data file that stores your messages and other items on your computer. You can assign a .pst file to be the default delivery location for e-mail messages. You can use a .pst to organize and back up items for safekeeping.) format was introduced that supports multilingual Unicode (Unicode: A character encoding standard developed by the Unicode Consortium. By using more than one byte to represent each character, Unicode enables almost all of the written languages in the world to be represented by using a single character set.) data and offers greater storage capacity for items and folders. You can determine whether your Outlook Data Files (.pst) are in the current or earlier format.

  1. Click the File tab.
  2. Click Account Settings, and then click Account Settings.

Account Settings in the Backstage view

  1. On the Data Files tab, select the data file that you want to verify, and then click Settings.
  2. Check the Format box to see if it contains the text Outlook Data File or Outlook Data File (97-2002).

Outlook Data File indicates the new format that supports multilingual Unicode data and offers greater storage capacity for items and folders. This file format is incompatible with Outlook 97-2002. Outlook Data File (97-2002) indicates the earlier format that is compatible with all versions of Outlook.

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Applies to:
Outlook 2010