Email Migration

How to Fix MigrationRecipientNotFoundException During Exchange Migration

Maira Mehtab Sep 24, 2026 869 views

Question details

The user needs to resolve an error where an Exchange migration batch fails to locate the target recipient in Microsoft 365.

Product: Exchange Server / Exchange Online
Device & OS: not provided
Scenario: Migrating mailboxes from an on-premises Exchange Server environment to Exchange Online in Microsoft 365.
Observed behavior: The migration batch fails and throws a MigrationRecipientNotFoundException error because the required recipient account is missing in the target cloud environment.

Before you start

Verify that your Microsoft Entra Connect (Azure AD Connect) directory synchronization is actively running without errors and that the latest sync cycle has completed.

Solution 1Recommended

Verify Directory Synchronization and Recipient Attributes

Ensure that directory synchronization has properly created the mail-enabled user in Microsoft 365 and that all proxy addresses match the on-premises configuration.

This error typically occurs when the target environment does not recognize the mail-enabled recipient. In an Exchange hybrid deployment, you must rely on directory synchronization to populate cloud users with the correct Exchange attributes from your on-premises Active Directory before attempting a mailbox migration.

Check the Microsoft 365 Admin Center

Log in to the Microsoft 365 Admin Center, navigate to 'Users', and select 'Active users'. Search for the recipient's name or email address to verify the account exists in the cloud.

Verify Proxy Addresses

Open the user's properties and check the aliases/email addresses tab to confirm that the target routing address (e.g., user@domain.mail.onmicrosoft.com) and primary SMTP address exactly match your on-premises configuration.

Force a Directory Sync

If the user is missing from the Microsoft 365 Admin Center, open PowerShell on your AD Connect server and execute 'Start-ADSyncSyncCycle -PolicyType Delta' to force an immediate synchronization to the cloud.

Consult the Microsoft Community

Since this is an Exchange hybrid migration issue, if the user exists but the error persists, post your detailed migration batch logs in the Microsoft Exchange Hybrid Management community for specialized technical guidance.

Hybrid Migration Requirement: Do not manually create the cloud mailbox to bypass this error. The user object must be synced from on-premises to correctly link the identity and avoid duplicate or orphaned accounts.

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Frequently Asked Questions

What does the MigrationRecipientNotFoundException error mean?

This error means the Exchange Online migration service cannot find a matching mail-enabled user object in the Microsoft 365 target environment, preventing the mailbox data from being migrated.

How long does it take for a new on-premises user to sync to Microsoft 365?

By default, Azure AD Connect synchronizes directory changes every 30 minutes. You can manually force a delta sync using PowerShell if you need the account to appear in the cloud immediately.

Should I manually create the missing user in Microsoft 365 Admin Center?

No. In an Exchange Hybrid setup, users must be created on-premises and synchronized to the cloud. Manually creating the user in Microsoft 365 can lead to synchronization conflicts and duplicate identities.

Migration & Recovery