CodeTwo Outlook Sync: Complete Setup Guide for 2025

How to Migrate Calendars with CodeTwo Outlook SyncMigrating calendars — whether moving from one account to another, centralizing team schedules, or consolidating multiple calendars after an organizational change — is a task that requires care to avoid data loss, duplicate events, or broken meeting invitations. CodeTwo Outlook Sync is a tool designed to synchronize Outlook data (including calendars) between multiple devices and accounts, making calendar migration smoother and more controllable. This guide walks through planning, preparation, step-by-step migration using CodeTwo Outlook Sync, troubleshooting, and best practices.

Overview: When to use CodeTwo Outlook Sync for calendar migration

CodeTwo Outlook Sync is appropriate when you need to:

• Synchronize calendars between two or more Outlook profiles on different machines.
• Migrate calendar items between accounts without using server-side tools.
• Maintain attendees, recurrence patterns, reminders, and attachments during migration.
• Keep a continuous sync for a transition period (two-way sync) before decommissioning the source.

If you’re moving large numbers of users across Exchange environments or to Microsoft 365 and need server-side migration (preserving id properties, organizer changes at server level), a dedicated migration tool or Microsoft-native solutions might be preferable. For device-to-device or profile-to-profile migrations where preserving event details and attendee status is the priority, CodeTwo Outlook Sync is a good fit.

Pre-migration checklist

• Backup mailboxes and calendars. Export PSTs or use your organization’s backup solution.
• Inventory calendars. Note which calendars will be migrated, ownership, and shared permissions.
• Check Outlook versions. Ensure all machines run supported versions of Outlook for the CodeTwo version you use.
• Install CodeTwo Outlook Sync on both source and target machines. You’ll need the app running where the source Outlook and target Outlook profiles are accessible.
• Coordinate with users. Inform meeting owners and attendees about expected downtime or changes to invites.
• Disable automatic rules that might move or alter calendar items during migration (e.g., auto-accept meeting requests).
• Confirm timezone settings on both source and target Outlook profiles to prevent event time shifts.
• Ensure network connectivity between devices (for LAN sync) or confirm both devices have internet access if using CodeTwo’s cloud features (depending on the product edition).

Types of migration workflows with CodeTwo Outlook Sync

• One-way sync (Source → Target): Useful when you want to copy calendars to a new account but keep source as the master.
• Two-way sync: Keeps both calendars in sync during a transition period; changes propagate both ways.
• Selective sync: Sync only specific folders, date ranges, or item types.
• Batch sync across multiple machines: Useful for migrating multiple users where a central admin oversees the process.

Step-by-step migration (typical LAN-based device-to-device migration)

1. Install and configure CodeTwo Outlook Sync

   • Download the installer from CodeTwo and run it on both the source and target machines.
   • Follow on-screen prompts to install. Restart Outlook if required.

2. Create a new sync pair

   • Open CodeTwo Outlook Sync on the source PC.
   • Click to create a new sync pair (or “Add sync pair”).
   • Select the source Outlook calendar folder (usually “Calendar”) as the folder to sync.
   • On the target PC, open CodeTwo and set the corresponding target folder (the destination Calendar in the target Outlook profile).

3. Choose sync direction and options

   • Select one-way or two-way synchronization depending on your plan.
   • Choose filters if you want to sync only a subset (date range, categories, or items created by specific users).
   • Configure conflict resolution rules (e.g., Prefer newer item, Prefer source item).

4. Map users and mailboxes (if applicable)

   • If syncing calendars between different Outlook profiles or mailboxes on the same machine, map the source mailbox to the target mailbox properly.
   • Verify attendee and organizer mapping so meeting invitations remain valid.

5. Start a test sync

   • Run the sync in test or dry-run mode if available. Check for errors or unexpected duplicates.
   • Verify several representative events: single-instance meetings, recurring meetings, meetings with attachments, and meetings with attendees.

6. Perform the full sync

   • Start the full synchronization.
   • Monitor the sync progress in the CodeTwo console. Larger calendars may take time — initial sync can be slow depending on item count and attachments.

7. Verify results

   • On the target Outlook, inspect migrated events for correctness: times, recurrence patterns, reminders, attachments, and attendee responses.
   • For meetings with attendees, confirm that organizers and attendee statuses were preserved or properly translated.

8. Post-migration cleanup

   • Disable the sync pair if you no longer want ongoing synchronization.
   • Re-enable any Outlook rules or automated processes you disabled earlier.
   • Communicate to users that migration is complete.

Common issues and fixes

• Event times shifted after migration
  • Check time zone settings in both Outlook profiles and Windows. Ensure DST settings match.
• Duplicate events after two-way sync
  • Resolve by adjusting conflict rules and re-running sync with duplicate detection enabled.
• Missing attendee responses or organizer changed
  • Verify mapping rules and ensure mailbox permissions allow the target to read meeting properties. For complex organizer ownership changes, consider re-inviting attendees from the target calendar.
• Sync fails with errors about Outlook not running
  • Ensure Outlook is running and the correct profile is active when CodeTwo runs. Run CodeTwo with sufficient permissions.
• Large attachments slow sync
  • Filter out attachments or run initial sync during off-hours. Consider archiving very large items separately.

Best practices and tips

• Migrate in phases: start with a few pilot users before mass migration.
• Use one-way sync for initial copy, then switch to two-way for cutover days to limit risk.
• Keep clear communication with meeting owners. Owners may need to re-send some invites if organizer properties can’t be preserved.
• Maintain backups (PST or server backups) until you’re certain migration is successful.
• Test recurring items and exceptions thoroughly — these are common failure points.
• If migrating many users, script installations and settings where possible, and consider centralized management if your edition supports it.

When to involve Exchange/Microsoft 365 admins or use a different tool

• You need to preserve server-side metadata (e.g., Exchange item IDs) for compliance or custom integrations.
• You’re migrating hundreds or thousands of mailboxes — use enterprise migration tools or Microsoft native migration services for scalability.
• Dealing with cross-tenant migrations where organizer/attendee relationships must remain intact at server level — consider tenant-to-tenant migration services.

Quick troubleshooting checklist

• Are both Outlook instances on the latest supported versions?
• Is Outlook running with the correct profile on both machines?
• Are time zones identical?
• Are mailbox permissions sufficient?
• Is CodeTwo allowed through firewall/antivirus?
• Are there filters that unintentionally exclude items?

Summary

Using CodeTwo Outlook Sync to migrate calendars offers a flexible, device-level approach that preserves most event details and attendee data when done carefully. The process involves planning, backups, configuring sync pairs, testing, performing the sync, and verifying results. For large-scale or server-level migrations, consider native Exchange/365 tools or enterprise migration services.

If you want, I can:

• Provide a concise migration checklist you can print or share.
• Create step-by-step instructions tailored to your specific Outlook versions and environment.