How do I migrate to Office 365 or Exchange 2007, 2010, 2013, or 2016 using delegation?
Please refer to the section that applies to the appropriate Destination. This article refers to the use of delegation to log in to individual user mailboxes using an "admin" account that has full access rights to each mailbox.
Note: We strongly recommend using impersonation, rather than just delegation, when migrating to Office 365. However, when migrating to Exchange, rather than Office 365, either delegation or impersonation can be used. Refer to KB005004 for more information on this decision, and the exact steps to set these up.
Having administrative access to the Microsoft Office 365 control panel to manage users does not neccessarily mean that the same account has permissions to access all mailboxes for migration. In order to have administrative permissions to migrate mailbox data, it is necessary to grant the account permissions on each mailbox.
To manually grant administrative access for migration, execute the following remote PowerShell command:
$cred = Get-Credential
$session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://ps.outlook.com/powershell/ -Credential $cred -Authentication Basic -AllowRedirection
Get-Mailbox -ResultSize Unlimited | Add-MailboxPermission -AccessRights FullAccess -Automapping $false -User MigrationWiz
To automatically create an administrative account and grant administrative access for the migration, download our script to provision an administrative account for migration on Microsoft Office 365.
To manually grant administrative access for migration, execute the following PowerShell command in the Exchange PowerShell Console:
Once completed, disable throttling against this "admin" account in order to speed up the migrations. Option 1 in KB004945 provides the exact steps to disable throttling against this account.