Comprehensive Guide to Assigning Permissions for Migrating On-Premises Exchange Mailboxes to Microsoft 365

Migrating mailboxes from an on-premises Exchange environment to Microsoft 365 or Office 365 requires careful planning and execution. A critical aspect of this process is ensuring that the migration administrator account has the appropriate Exchange permissions. This guide covers the permissions required for different migration types and provides detailed steps to configure them. Additionally, discover how Medha Cloud can support and simplify your migration process.

Key Role of the Migration Administrator

The migration administrator is the account used to create a migration endpoint and execute mailbox migrations. It requires specific administrative privileges within your on-premises Exchange environment. The Exchange permissions vary depending on the type of migration:

Types of Exchange Migrations and Required Permissions

1. Staged Exchange Migration

• Permissions Required:
  • Member of the Domain Admins group in Active Directory Domain Services (AD DS).
  • OR FullAccess permission for each mailbox and WriteProperty permission for the TargetAddress property.
  • OR Receive As permission on the mailbox database and WriteProperty permission for the TargetAddress property.

2. Cutover Exchange Migration

• Permissions Required:
  • Member of the Domain Admins group in AD DS.
  • OR FullAccess permission for each mailbox.
  • OR Receive As permission on the mailbox database.

3. Remote Move (Hybrid) Exchange Migration

• Permissions Required:
  • Member of the Domain Admins group in AD DS.
  • OR Member of the Exchange Recipient Administrators group in AD DS.
  • OR Member of the Organization Management role group in Exchange 2010 or later.

4. IMAP4 Migration

• Permissions Required:
  • The username and password for each mailbox.
  • OR The username and password of an administrative account with access to all mailboxes in the IMAP4 system.

Note: For Exchange Server 2003, you must use Active Directory Users and Computers to assign FullAccess and Exchange System Manager to assign Receive As permissions.

Step-by-Step Guide to Assign Exchange Permissions

The following examples show how to use the Exchange Online PowerShell cmdlet to give the migration administrator account full access to mailboxes in your organization.

Assigning FullAccess Permission

1. For a Single Mailbox:

PowerShell Code

Add-MailboxPermission -Identity “Terry Adams” -User migadmin -AccessRights FullAccess -InheritanceType all

2. For a Distribution Group:

Get-DistributionGroupMember MigrationBatch1 | Add-MailboxPermission -User migadmin -AccessRights FullAccess -InheritanceType all

3. For Specific Attribute-Based Mailboxes:

Get-Mailbox -ResultSize unlimited -Filter “CustomAttribute10 -eq ‘MigBatch2′” | Add-MailboxPermission -User migadmin -AccessRights FullAccess -InheritanceType all

4. For All User Mailboxes:

Get-Mailbox -ResultSize unlimited -Filter “RecipientTypeDetails -eq ‘UserMailbox'” | Add-MailboxPermission -User migadmin -AccessRights FullAccess -InheritanceType all

Assigning Receive As Permission

Add-ADPermission -Identity “Mailbox Database 1900992314” -User migadmin -ExtendedRights receive-as

Assigning WriteProperty Permission

1. For a Single User Account:

Add-ADPermission -Identity “Rainer Witte” -User migadmin -AccessRights WriteProperty -Properties TargetAddress

2. For a Distribution Group:

Get-DistributionGroupMember StagedBatch1 | Add-ADPermission -User migadmin -AccessRights WriteProperty -Properties TargetAddress

3. For Attribute-Based User Accounts:

Get-User -ResultSize unlimited -Filter “CustomAttribute15 -eq ‘StagedMigration'” | Add-ADPermission -User migadmin -AccessRights WriteProperty -Properties TargetAddress

4. For All User Accounts:

Get-User -ResultSize unlimited -Filter “RecipientTypeDetails -eq ‘UserMailbox'” | Add-ADPermission -User migadmin -AccessRights WriteProperty -Properties TargetAddress

Verifying Permission Assignments

Check FullAccess Permissions:

Get-MailboxPermission -Identity -User migadmin

Check Receive As Permissions:

Get-ADPermission -Identity “Mailbox Database 1900992314” -User migadmin

Check WriteProperty Permissions:

Get-ADPermission -Identity -User migadmin

How Medha Cloud Simplifies Exchange Migrations

Medha Cloud offers expert services to ensure a seamless Exchange migration to Microsoft 365. From preparing your environment to assigning permissions and ensuring compliance, Medha Cloud can handle all aspects of your migration project. Our team of certified professionals leverages advanced tools and best practices to minimize downtime and maximize efficiency during the transition.

Final Thoughts

Migrating mailboxes from an on-premises Exchange environment to Microsoft 365 requires meticulous preparation and the right Exchange permissions. By following this guide, you can ensure a smooth migration process. However, managing such migrations can still be a complex task. Partnering with Medha Cloud ensures that your migration is executed with precision and expertise, leaving your organization poised for future growth and productivity in the Microsoft 365 ecosystem. Contact Medha Cloud today to streamline your migration journey!

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