OST Files Vs. PST Files
Both OST files and PST files is part of MS Outlook, as you know that PST File is Personal Storage Data Table which store all personal E-mail and their attributes but OST files is created by MS Exchange Server that's keeps E-mail record on off-line mode in client machine. When Outlook user does work on off-line or server downtime, OST file play vital role to help in recovery of E-mail with OST File Repair tool.
More About Outlook OST File Manager Tool
You read more about individual freeware product:
OST File Viewer
It is a marvelous tool to quickly scan unreadable OST file and view including Emails, Contacts, Calendars, Tasks, and Journals.
OST File Locater
Tool to search out OST file with their properties and including details from multiple locations existing in the client machine.
OST File Finder
Tool to search in all system drives and find out offline storage table (.ost) file as well as exports searched list of OST file into CSV file.
You Can Also Read About Useful OST Converter
OST to PST Converter
Magnificently convert unreadable offline Outlook OST file into readable PST file including entire email properties.
OST to PDF Converter
Successfully save multiple emails of Outlook OST file into PDF file format including emails, contacts, journal, task etc.
Batch OST to PST
Quickly convert multiple unworkable or corrupted OST file into usable PST file. User can also save it into EML or MSG file.