File Extension PST

  • Full name
    Microsoft Outlook Personal Folder Format
  • Developer
  • Popularity
Have you encountered a problem with a PST file? Don’t you know which program opens a file with this extension? You will find all the information you need about working with a PST file here. In the further part of this page we have added a list of programs that should open your PST file. It is enough you choose a proper application for your operating system, download and install it.


A PST file is a so-called Personal Storage Table, ie a storage for personal data. PST is a proprietary but open format used by Microsoft Outlook and Microsoft Exchange to manage contact information. Microsoft Outlook is a contact manager and part of Microsoft Office. Pst files are data containers that contain, among other things, emails, addresses, calendar data and tasks.

In addition to a standard PST file, Outlook can also manage multiple PST files. Since there are always problems with corrupt PST files, it is recommended to create backups regularly, taking into account that, among other things, account and program settings are not saved in the PST file. To repair defective PST files, the program scanpst is installed with Outlook.

The maximum file size of a PST file can now (from Outlook 2003) be up to 20 GB, before that it was only 2 GB. Very large PST files can cause Outlook to slow down noticeably. Defragmenting the hard disk or archiving old emails can help here.

The free Outlook Express does not use PST files but can import them. Since the PST format is open, other mail programs can also import PST files, for example Thunderbird. Since the PST format has meanwhile been changed several times, problems can occur during import. Unfortunately, most programs rely on Outlook being installed to import a .pst file.

Programs which can open a PST file

How to open a PST file? Advice and guidance

Absolutely most often appearing reason that prevents you from opening the PST file is the lack of a proper application to support it in your operating system. It is notably the first thing you need to address. When one of the programs to support a PST file from the list is already installed, you can try to rerun the file. The system should display a message asking you to choose a primary application to support PST files. At this point we are looking for disk space where the application was installed in and we can link it with a PST file. Since then, our operating system will use the selected program to support all PST files.

Other issues

Despite the described problem with PST there may be many more problems. If the existing operations were not effective, get involved with the following matters:

- verify that the PST file is not damaged and that it has been downloaded or copied in whole
- verify that the file has a file extension that has not been intentionally changed (for example, if it do not contain other information than its extension suggests)
- make sure again whether the PST file type is linked in the operating system with a proper program
- make sure that the file is not infected with a virus and you have up to date software and drivers.

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