Windows
Compatible applications
Quick Facts
Basic information about this file format
Extension
.PST
File Type
Personal Storage Table
Category
Data
Best first step
Use compatible software
Quick Summary
A practical overview of the .pst file format
A PST file, which stands for Personal Storage Table, is a proprietary file format developed by Microsoft to store local copies of messages, calendar events, and other items within Microsoft software such as Microsoft Outlook, Microsoft Exchange Client, and Windows Messaging. These files are primari…
File extension
.PST
File type
Personal Storage Table
Category
Data
Recommended action
Open with a trusted compatible app
How to open a .pst file
Start with a trusted app that supports this format
- Check the file extension carefully and confirm that the file name really ends with .pst.
- Use software that supports this file type. If one app does not work, try another compatible program for the same platform.
- Update the application if the file was created by a newer version of the software.
- Scan files from unknown sources before opening them, especially documents, archives, scripts, installers, and executable files.
What is a .pst file?
File extension details and usage information
A PST file, which stands for Personal Storage Table, is a proprietary file format developed by Microsoft to store local copies of messages, calendar events, and other items within Microsoft software such as Microsoft Outlook, Microsoft Exchange Client, and Windows Messaging. These files are primarily used to archive older emails or to keep a local backup of mailbox data that exceeds server storage limits. Unlike OST files, which are offline caches of server data, PST files are independent and can be moved between different computers or stored on external drives. They contain a structured database of folders, including the Inbox, Sent Items, Drafts, and custom user-created folders, along with attachments, contacts, tasks, and notes. Over the years, the format has evolved from the older ANSI format, which had a 2GB size limit, to the modern Unicode format used since Outlook 2003, which supports much larger file sizes, typically up to 50GB by default. Managing PST files is crucial for enterprise data retention and personal email organization, though they are prone to corruption if the file size becomes excessively large or if the network connection is interrupted during access. Because it is a proprietary format, opening PST files usually requires specific Microsoft software or specialized third-party conversion tools.
Software Compatibility
Programs that may open or work with .pst files
macOS
Compatible applications
Linux
Compatible applications
Mobile
Mobile applications
Can .pst files be converted?
Options for saving or exporting this file to another format
In many cases, a .pst file can be converted by opening it in compatible software and using an option such as Save As, Export, or Convert. The available output formats depend on the file type and the application used.
- Use the original software that created the file when possible.
- Check whether the application supports exporting to common formats.
- Be careful with online converters when working with private, business, or sensitive files.
- If conversion fails, the file may be corrupted, incomplete, encrypted, or not actually a .pst file.
Why can't I open a .pst file?
Common reasons this file type may not open correctly
Wrong software
The file may require a specific program that supports the .pst format.
Incorrect extension
The file extension may have been renamed manually, even though the actual file format is different.
Corrupted file
The file may be incomplete, damaged during download, or transferred incorrectly.
Outdated app
Your software may need to be updated before it can open newer versions of this file format.
Frequently Asked Questions
Common questions about .pst files
To open a .pst file, use software that supports this file format.
- Microsoft Outlook
- SysTools PST Viewer
- Kernel for PST Viewer
- Mailbird
- Microsoft Outlook for Mac
Open the file in compatible software and look for options such as Save As, Export, or Convert. If no export option is available, the file may require a specialized converter or the original application that created it.
- Verify that the file extension is correct.
- Install or update compatible software.
- Try another application that supports this format.
- Check whether the file is corrupted, incomplete, or encrypted.
A file extension alone does not guarantee whether a file is safe or unsafe. Only open files from trusted sources, scan unknown files before opening them, and be especially careful with executable, script, archive, and document files.
File safety tips
Use caution with unknown files
Only open files from trusted sources. Before opening a .pst file, scan it with antivirus software, verify that the file extension is expected, and avoid running unknown executable, installer, macro-enabled document, or script files.