When Microsoft Exchange users work in Outlook with an Exchange, Microsoft 365, or IMAP account, Outlook often creates an OST (Offline Storage Table) file. This file is designed to cache mailbox data locally so users can read emails, access calendars, and search items even when the network is unstable or the server is temporarily unavailable. But when an Exchange mailbox becomes inacce... https://news.bangboxonline.com/OST-to-PST-Converter-Tool-for-Offline-Exchange-Mailbox