A daily updated filename extension database!

OST file extension

The table below provides useful information about the .ost file extension. It answers questions such as:

  • What is the .ost file?
  • What program do I need to open a .ost file?
  • How can the .ost file be opened, edited or printed?
  • How can I convert .ost files to another format?

We hope you find this page helpful and a valuable resource!

1 extension(s) and 0 alias(es) found in database

✅ Microsoft Outlook Offline Folder File

OST file is a Microsoft Outlook Offline Folder File.
OST format description not yet available
Category: Data files
Application: Microsoft Outlook
Mime-type: application/octet-stream
Magic number: -
Magic string: -
Sample: -
OST aliases:
OST related links:
OST related extensions:
Microsoft Outlook Navigation Bar

Microsoft Outlook Template

Microsoft Outlook Profile

Microsoft Outlook Personal Folder File

Microsoft Outlook Form Storage

Microsoft Outlook Rules Wizard

Microsoft Outlook Personal Address Book

Microsoft Outlook 2000 Auto Complete Nick List

Microsoft Outlook 2002 Auto Complete Nick List

Microsoft Outlook Send/Receive Settings

Other types of files may also use the .ost file extension.

🚫 The .ost file extension is often given incorrectly!

According to the searches on our site, these misspellings were the most common in the past year:

ist, kst, lst, oct, oet, os, osf, osg, osh, osr, ot, ots, owt, oxt, ozt

Is it possible that the filename extension is misspelled?

We found the following similar file extensions in our database:

Hollowcore Manufacturing System SOT Data
Adventure SOS Walkthrough Source
CET Designer ProjectSymbols Standard Options Table
Adobe ImageStyler File
IBM InfoSphere Schema Data
eSignal Order Entry Ticket Data
GCC Assembler Listing File
MU Online Image
Digitrakker Instrument Data
Osu! Replay File

🔴 Can't open a .ost file?

When you double-click a file to open it, Windows examines the filename extension. If Windows recognizes the filename extension, it opens the file in the program that is associated with that filename extension. When Windows does not recognize a filename extension, you receive the following message:

Windows cannot open this file:


To open this file, Windows needs to know what program you want to use to open it...

If you don't know how to set the .ost file association, check the FAQ.

🔴 Can I change the extension of files?

Changing the filename extension of a file is not a good idea. When you change a file's extension, you change the way programs on your computer read the file. The problem is, changing the file extension does not change the file format.

If you have helpful information about the .ost file extension, write to us!

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