Synchronization requires an active network connection with the mailbox server. Methods to Resolve IMAP Sync Issue in Outlook 2019, 2016, or 2013īelow we have discussed some methods to troubleshoot and fix Outlook 2019, 2016, or 2013 Sync Issues. 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.
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.