Some of the user faced an issue that they are unable to analyze the file format of Outlook PST File whether it is in ANSI (American National Standard Instructions Codes) or in UNICODE.

Outlook Data file supports two formats i.e. ANSI and UNICODE.  In Outlook 2003 and older version, the file format of Outlook PST file is ANSI and in Microsoft Outlook 2003, 2007, 2010, 2013 and 2016 PST file saves UNICODE format by default. But, Outlook 2003 and above versions also support ANSI format.

Apart from this, let’s come to the size:

Microsoft Outlook 2002 and below versions:  Supports PST up to 2GB.

Microsoft Outlook 2003 and 2007: Supports PST up to 20GB.

Microsoft Outlook 2010 and 2013: Supports PST up to 50GB and can be extended up to 4PB.

Steps to know the format of Outlook PST File:

Follow the given below steps and conclude the PST File is in ANSI or UNICODE:

Steps in Outlook 2010, 2013 and 2016:

  • Open “Microsoft Outlook” >> Click on “File” tab >> “Info” (at left pane) >> “Account Settings” >> “Account Settings” >> hit on “Data Files”.
  • To check the file format, click twice on path which named as .pst extension.
  • A pop-up box will appear, go to the “Format:” field, if it named as “Outlook Data File” or “Personal Folder File”,  then you are using UNICODE PST format.
  • If it named as “Personal Folders File (97-2002)” or “Outlook Data File (97-2002)”, then you are working on ANSI PST format.

Steps in Microsoft Outlook 2003 and 2007:

  • Open “Microsoft Outlook” >> Click on “File” tab >> go to “Data File Management” >> hit on “Data Files”.


Advantages of UNICODE PST format file:

As I already discussed about the size of UNICODE and ANSI PST formats in above section. The main advantage of UNICODE PST formats are:

  • It supports Outlook PST File up to 20 GB and extendable.
  • Due to the size, In Unicode Outlook hanging, freezing, etc. problems occur less than ANSI.
  • Unlike ANSI, UNICODE format does not use different page for different languages.
  • UNICODE programs are faster than ANSI Programs.