Home : File Types : OST File

.OST File Extension

File TypeOutlook Offline Folder File

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CategoryMisc Files


This file is saved in a binary format, which requires a specific program to read its contents.

What is a OST file?

Stores e-mail messages and other data saved by Microsoft Outlook (2005 or later) from an Exchange server; similar to a Personal Folder (.PST) File, but supports larger file sizes.

More Information

OST files are created when the "Use Offline Folders" option is selected in Outlook and are stored on the local hard drive instead of mail server.

Open over 300 file formats with File Viewer Plus.
Programs that open OST files
Microsoft Outlook 2016
Remo Convert OST to PST
OEMailRecovery.com Outlook Recovery Toolbox
Updated 9/18/2015

.OST Extension Information

This page contains information about the file extension OST and its known file associations. Our goal is to help you understand what a *.ost file is and how to open it.

The Outlook Offline Folder file type, file format description, and programs listed on this page have been individually researched and verified by the FileInfo team. We strive for 100% accuracy and do not publish any information we have not verified.

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