Migrate Exchange 2003 to Office 365

Tutorial on how to Migrate Exchange 2003 to Office 365 with CodeTwo Office 365 Migration using the same lab prepared for Migration from Windows 2003 AD to 2016

Install Azure AD Connect by following Azure AD Connect for Exchange Hybrid Migration but DO NOT check Exchange Hybrid Deployment

Select Azure AD App and Attribute Filtering

Click Next to continue

Uncheck msExchMailboxGuid to allow Office 365 to provision a New Mailbox for Users

Verify AD Users are synchronized to Office 365

Get-MsolUser | ? LastDirSyncTime -NE $null | Select DisplayName, UserPrincipalName, LAstDirSyncTime, IsLicensed

DisplayName                                           UserPrincipalName                                         LastDirSyncTime      IsLicensed
-----------                                           -----------------                                         ---------------      ----------
UAT4 TEST                                             [email protected]                                           6/13/2020 7:08:49 PM       True
On-Premises Directory Synchronization Service Account [email protected] 6/13/2020 6:17:09 PM      False
UAT2 TEST                                             [email protected]                                           6/13/2020 7:08:49 PM       True

CodeTwo Office 365 Migration is used to migrate existing mailbox from Exchange 2003 to Office 365

Download CodeTwo Office 365 Migration 30 Days License which can be used to migrate first 10 items only

Messaging API and Collaboration Data Objects Package will be installed

Click Next

Click I Accept the terms and Licenses Agreement to continue

Accept the default installation path C:\Program Files (x86)\CodeTwo\Office 365 Migration

Click Create a new migration job

Select Exchange Server

Enter a job name called ExchangeToO365

Select Add New Source Connection to connect to Exchange 2003 Server

Select MAPI Protocol

Click Yes to continue

Select Autodiscover Exchange Server or enter the Exchange 2003 server manually

Enter Credential of Domain Admin

Click Configure to continue

Ensure that it can connect to Exchange 2003 successfully

Click Next to continue

Select Add New Target Connection to define the connection to Office 365

Select Office 365 Global

Select Automatic Registration and click Log in Office 365 Admin

You might encounter the following error message if Active Scripting is NOT enabled in Internet Explorer (IE)

Go to Internet Option – Security – Internet – Custom Level – Scripting – Active Scripting to enable Active Scripting

Click Accept

Click Configure to continue

Ensure that the connection to Office 365 is configured successfully.

Click Next to continue

Click Next to continue

Click Yes to continue and we will match the mailbox manually later

Do NOT enable Scheduler and click Next to continue

Select Migrate all items regardless of thier age

Click Next to continue

Click Next to continue

Click Finish

Migration Job is created successfully

All the mailboxes in Exchange 2003 will be listed automatically. Right click on the user’s mailbox and select Match Target Mailbox to migrate all user’s folders in thier mailbox to Office 365

Select Choose an existing user from the list or Manually enter existing mailbox address if user’s UPN is different with thier Email Address

Select the User account in Office 365

Click Start and CodeTwo will perform the following tasks automatically

• Assign Office 365 License to the user
• Provision a new empty mailbox in Office 365
• Migrate all folders in User’s Mailbox to the new Mailbox in Office 365

Verify the Migration Status changed to Finished once all the folders had been copied to the new mailbox in Office 365

Right Click on the user account and select View Mailbox Report to verify all items are copied successfully

Click on Job in Reports tab to generate Migration Status Report

Steps to perform Cut Over Migration

• Update the existing Autodiscover & MX records to point to Office 365
• Create a new profile in Microsoft Outlook to point Office 365
• Verify all the users’ previous folders are synchronized to thier new mailbox successfully

Lastly, click Rescan to perform synchronization for any latest items delivered to Exchange 2003 since last full synchronization to Office 365.

We had used CodeTwo Office 365 Migration Manager to complete the migration of 200 users’ mailbox from Exchange 2003 to Office 365 successfully within one week without any major issue encountered.

Login to Office 365 & Exchange Online with PowerShell

$OldUPN = "[email protected]"
$NewUPN = "[email protected]"

Set-MsolUserPrincipalName -UserPrincipalName $OldUPN -NewUserPrincipalName $NewUPN