

Check your system for these security updates and uninstall them. NOTE: Security Updates KB2837618 or KB2837643 cause problems, such as synchronization issues in the Outlook IMAP account.

Thus, fixing the IMAP Sync Issues is critical.

With proper settings and configuration, the synchronization between the Outlook client and mailboxes server ensures uninterrupted email flow. Any changes made, such as drafting a new email or deleting messages, etc., are stored in the Offline OST file and synchronized with the mailbox server. When configured with an IMAP-based email account, Outlook creates an OST Outlook data file to store an offline synchronized copy of mail items, such as emails, contacts, attachments, notes, tasks, etc. Methods to Resolve IMAP Sync Issue in Outlook 2019, 2016, or 2013.
