If you ask how to reduce size of OST file in Outlook? So this is a very simple job for eSoftTools OST to PST converter software. First of all convert OST mailbox item to Outlook format like sent item, attachment, calendar, outbox, inbox to PST, EML, MBOX, MSG, ICS, Yahoo, Gmail, Office 365, vCard, EMLX, HTML, and any format. Use the free demo version and you can convert 25 items in any folder.
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