Inconsistent number of emails or mail items sent or received via Outlook client and OWA.

Missing emails, attachments, contacts, notes, calendar items, journal entries, shared folder or mail items in OWA or mailbox server.Error messages while synchronizing the mail items manually with the mailbox server.Prevent users from sending or receiving new emails.This indicates Outlook synchronization issue, which can lead to severe problems such as, This two-way synchronization keeps both-the local cache (.OST) and mailbox server-updated.īut sometimes, Exchange or Microsoft 365 (Office 365) users may encounter discrepancies between their Outlook client and Outlook Web App, such as outdated or missing messages and mail items. Similarly, updates on Outlook Web App (OWA), such as sending or receiving new emails, calendar or Shared mailbox folder updates, etc., are saved on the mailbox server and synchronized with the Outlook OST automatically. Outlook creates a local Offline Storage Table or OST file (also known as Offline Folder) when users add or configure their Exchange, Office 365 (Microsoft 365), IMAP, or account.Īny changes made by the user in their Outlook profile, such as drafting or deleting an email, are saved locally in the OST file and synchronized with the mailbox server later.

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