How to Determine if a PST is ANSI or Unicode

Friday, August 22, 2008

PSTs created in Outlook 2002 and earlier versions are saved in ANSI format, which has a 2.1GB limit. Outlook 2003 and later offer both ANSI and Unicode formats for PST creation. Unicode PSTs have a theoretical 36TB limit which makes them a better choice, providing that backward compatibility is not an issue.

So how can you tell if a PST is in ANSI or Unicode format?

One way is to download a free utility called ListPSTs from You run this utility from the command line against the file or folder that contains the PST(s). The output displays the format of the PST files, as shown above.

Another way to tell without having to use a separate utility is by viewing the properties of the PST from within Outlook, itself. When you add the PST to Outlook, pay attention to the Format field of the PST, as shown below:

Unicode formatted PSTs will display the format, "Personal Folders File". ANSI formatted PSTs will display the format, "Personal Folders File (Outlook 97-2002)".


  1. @Dane K, you can't use ListPST against a PST that's in use!

  2. Gee, would it be too much for MS to make that available in the File Properties information?

  3. no longer available. Anyone have this file?

  4. Many thanks for this. Please note also that if file format says "Outlook Data File" it is the Unicode Formatted.


Thank you for your comment! It is my hope that you find the information here useful. Let others know if this post helped you out, or if you have a comment or further information.