Quick answer
POP can leave the only copy of mail on one computer. Preserve local data and use the mailbox's secure POP/SMTP settings when planning a supported-client migration.
Applies to
Historical reference for Outlook 2016 while moving to a supported mail client. Microsoft ended Office 2016 support on October 14, 2025. Classic Outlook, new Outlook and other clients use different menus. Preserve local-only mail and contacts before migration.
Steps
- Confirm that POP is appropriate and verify a backup of required local mail. Review whether the server retains a copy.
- In the old manual account setup, select POP and enter the exact mailbox username and provider hostnames.
- Use the supported TLS/port pairs, commonly POP 995 and SMTP 465 with implicit TLS or 587 with STARTTLS. Do not select no encryption to match a demonstration.
Check the result
Test receiving and sending, then verify both local and server retention. A downloaded message may not be available on another device.
Troubleshooting and support
If mail disappears from other devices, inspect POP deletion/retention settings and backups before changing account type.
If the problem continues, contact support from the account that owns the service. Include the domain, exact error, time and time zone, tool name, and a redacted screenshot. Keep passwords, private keys, cookies and private message content out of the ticket.
Video tutorial
The original video is preserved. Its interface or product version may differ from the written guidance above.
Related help
- Find the correct secure IMAP and SMTP settings for your mailbox
- Use webmail to separate a mailbox problem from a device problem
Official references
Written content reviewed November 1, 2026. Menu availability depends on the product version, permissions and service.
