Migrate Microsoft Entra Connect Sync group writeback V2 to Microsoft Entra Cloud Sync

The following document describes how to migrate group writeback using Microsoft Entra Connect Sync (formerly Azure AD Connect) to Microsoft Entra Cloud Sync. This scenario is only for customers who are currently using Microsoft Entra Connect group writeback v2. The process outlined in this document pertains only to cloud-created security groups that are written back with a universal scope.

Prerequisites

The following prerequisites are required to implement this scenario.

• Microsoft Entra account with at least a Hybrid Identity Administrator role.
• An on-premises AD account with at least domain administrator permissions - required to access the adminDescription attribute and copy it to the msDS-ExternalDirectoryObjectId attribute
• On-premises Active Directory Domain Services environment with Windows Server 2016 operating system or later.
  • Required for AD Schema attribute - msDS-ExternalDirectoryObjectId
• Provisioning agent with build version 1.1.1367.0 or later.
• The provisioning agent must be able to communicate with the domain controller(s) on ports TCP/389 (LDAP) and TCP/3268 (Global Catalog).
  • Required for global catalog lookup to filter out invalid membership references

Naming convention for groups written back

By default, Microsoft Entra Connect Sync uses the following format when naming groups that are written back.

• Default format: CN=Group_<guid>,OU=<container>,DC=<domain component>,DC=<domain component>

• Example: CN=Group_3a5c3221-c465-48c0-95b8-e9305786a271,OU=WritebackContainer,DC=contoso,DC=com 

To make it easier to find groups being written back from Microsoft Entra ID to Active Directory, Microsoft Entra Connect Sync added an option to write back the group name by using the cloud display name. This is done by selecting the Writeback Group Distinguished Name with cloud Display Name during initial setup of group writeback v2. If this feature is enabled, Microsoft Entra Connect uses the following new format, instead of the default format:

• New format: CN=<display name>_<last 12 digits of object ID>,OU=<container>,DC=<domain component>,DC=<domain component>

• Example: CN=Sales_e9305786a271,OU=WritebackContainer,DC=contoso,DC=com 

Using the default format

If you want cloud sync to use the same default format as Microsoft Entra Connect Sync, you need to modify the attribute flow expression for the CN attribute. The two possible mappings are:

For more information, see Add an attribute mapping - Microsoft Entra ID to Active Directory

Step 1 - Copy adminDescription to msDS-ExternalDirectoryObjectID

To validate group membership references, Microsoft Entra Cloud Sync must query the Active Directory Global Catalog for msDS-ExternalDirectoryObjectID attribute. This is an indexed attribute which replicates across all Global Catalogs within the Active Directory Forest.

1. In your on-premises environment, open ADSI Edit.

2. Copy the value that it in the group's adminDescription attribute

   

3. Paste in to the msDS-ExternalDirectoryObjectID attribute

   

The following PowerShell script can be used to help automate this step. This script takes all of the groups in the OU=Groups,DC=Contoso,DC=com container and copy the adminDescription attribute value to the msDS-ExternalDirectoryObjectID attribute value. Before using this script, update the variable $gwbOU with the DistinguishedName of your group writeback's target organizational unit (OU).

# Provide the DistinguishedName of your Group Writeback target OU
$gwbOU = 'OU=Groups,DC=Contoso,DC=com'

# Get all groups written back to Active Directory
$properties = @('displayName', 'Samaccountname', 'adminDescription', 'msDS-ExternalDirectoryObjectID')
$groups = Get-ADGroup -Filter * -SearchBase $gwbOU -Properties $properties | 
    Where-Object {$_.adminDescription -ne $null} |
        Select-Object $properties

# Set msDS-ExternalDirectoryObjectID for all groups written back to Active Directory 
foreach ($group in $groups) {
    Set-ADGroup -Identity $group.Samaccountname -Add @{('msDS-ExternalDirectoryObjectID') = $group.adminDescription}
} 

The following PowerShell script can be used to check the results of the script above or confirm that all groups have adminDescription value equal to msDS-ExternalDirectoryObjectID value.

# Provide the DistinguishedName of your Group Writeback target OU
$gwbOU = 'OU=Groups,DC=Contoso,DC=com'


# Get all groups written back to Active Directory
$properties = @('displayName', 'Samaccountname', 'adminDescription', 'msDS-ExternalDirectoryObjectID')
$groups = Get-ADGroup -Filter * -SearchBase $gwbOU -Properties $properties | 
    Where-Object {$_.adminDescription -ne $null} |
        Select-Object $properties

$groups | select displayName, adminDescription, 'msDS-ExternalDirectoryObjectID', @{Name='Equal';Expression={$_.adminDescription -eq $_.'msDS-ExternalDirectoryObjectID'}}

Step 2 - Place the Microsoft Entra Connect Sync server in staging mode and disable the sync scheduler

1. Start the Microsoft Entra Connect Sync wizard

2. Click Configure

3. Select Configure staging mode and click Next

4. Enter Microsoft Entra credentials

5. Place a check in the Enable staging mode box and click Next

   

6. Click Configure

7. Click Exit

   

8. On your Microsoft Entra Connect server, open a PowerShell prompt as an administrator.

9. Disable the sync scheduler:

   Set-ADSyncScheduler -SyncCycleEnabled $false  
   

Step 3 - Create a custom group inbound rule

In the Microsoft Entra Connect Synchronization Rules editor, you need to create an inbound sync rule that filters out groups that have NULL for the mail attribute. The inbound sync rule is a join rule with a target attribute of cloudNoFlow. This rule tells Microsoft Entra Connect not to synchronize attributes for these groups. To create this sync rule, you can opt to use the user interface or create it via PowerShell with the provided script.

Create a custom group inbound rule in the user interface

1. Launch the Synchronization Rules Editor from the start menu.

2. Select Inbound from the drop-down list for Direction and select Add new rule.

3. On the Description page, enter the following and select Next:

   • Name: Give the rule a meaningful name

   • Description: Add a meaningful description

   • Connected System: Choose the Microsoft Entra connector that you're writing the custom sync rule for

   • Connected System Object Type: Group

   • Metaverse Object Type: Group

   • Link Type: Join

   • Precedence: Provide a value that is unique in the system. Lower than 100 is recommended, so that it takes precedence over the default rules.

   • Tag: Leave empty

     

4. On the Scoping filter page, Add the following and then select Next.

   Attribute	Operator	Value
   cloudMastered	EQUAL	true
   mail	ISNULL

   

5. On the Join rules page, select Next.

6. On the Transformations page, add a Constant transformation: flow True to cloudNoFlow attribute.

   

7. Select Add.

Create a custom group inbound rule in PowerShell

1. On your Microsoft Entra Connect server, open a PowerShell prompt as an administrator.

2. Import the module.

   Import-Module ADSync
   

3. Provide a unique value for the sync rule precedence [0-99].

   [int] $inboundSyncRulePrecedence = 88
   

4. Execute the following script:

    New-ADSyncRule  `
    -Name 'In from AAD - Group SOAinAAD coexistence with Cloud Sync' `
    -Identifier 'e4eae1c9-b9bc-4328-ade9-df871cdd3027' `
    -Description 'https://zcusa.951200.xyz/entra/identity/hybrid/cloud-sync/migrate-group-writeback' `
    -Direction 'Inbound' `
    -Precedence $inboundSyncRulePrecedence `
    -PrecedenceAfter '00000000-0000-0000-0000-000000000000' `
    -PrecedenceBefore '00000000-0000-0000-0000-000000000000' `
    -SourceObjectType 'group' `
    -TargetObjectType 'group' `
    -Connector 'b891884f-051e-4a83-95af-2544101c9083' `
    -LinkType 'Join' `
    -SoftDeleteExpiryInterval 0 `
    -ImmutableTag '' `
    -OutVariable syncRule
   
    Add-ADSyncAttributeFlowMapping  `
    -SynchronizationRule $syncRule[0] `
    -Source @('true') `
    -Destination 'cloudNoFlow' `
    -FlowType 'Constant' `
    -ValueMergeType 'Update' `
    -OutVariable syncRule
   
    New-Object  `
    -TypeName 'Microsoft.IdentityManagement.PowerShell.ObjectModel.ScopeCondition' `
    -ArgumentList 'cloudMastered','true','EQUAL' `
    -OutVariable condition0
   
    New-Object  `
    -TypeName 'Microsoft.IdentityManagement.PowerShell.ObjectModel.ScopeCondition' `
    -ArgumentList 'mail','','ISNULL' `
    -OutVariable condition1
   
    Add-ADSyncScopeConditionGroup  `
    -SynchronizationRule $syncRule[0] `
    -ScopeConditions @($condition0[0],$condition1[0]) `
    -OutVariable syncRule
   
    Add-ADSyncRule  `
    -SynchronizationRule $syncRule[0]
   
    Get-ADSyncRule  `
    -Identifier 'e4eae1c9-b9bc-4328-ade9-df871cdd3027'
   

Step 4 - Create a custom group outbound rule

You also need an outbound sync rule with a link type of JoinNoFlow and the scoping filter that has the cloudNoFlow attribute set to True. This rule tells Microsoft Entra Connect not to synchronize attributes for these groups. To create this sync rule, you can opt to use the user interface or create it via PowerShell with the provided script.

Create a custom group outbound rule in the user interface

1. Select Outbound from the drop-down list for Direction and select Add rule.

2. On the Description page, enter the following and select Next:

   • Name: Give the rule a meaningful name
   • Description: Add a meaningful description
   • Connected System: Choose the AD connector that you're writing the custom sync rule for
   • Connected System Object Type: Group
   • Metaverse Object Type: Group
   • Link Type: JoinNoFlow
   • Precedence: Provide a value that is unique in the system. Lower than 100 is recommended, so that it takes precedence over the default rules.
   • Tag: Leave empty

   

3. On the Scoping filter page, choose cloudNoFlow equal True. Then select Next.

   

4. On the Join rules page, select Next.

5. On the Transformations page, select Add.

Create a custom group inbound rule in PowerShell

1. On your Microsoft Entra Connect server, open a PowerShell prompt as an administrator.

2. Import the module.

   Import-Module ADSync
   

3. Provide a unique value for the sync rule precedence [0-99].

   [int] $outboundSyncRulePrecedence = 89
   

4. Get the Active Directory Connector for Group Writeback.

   $connectorAD = Get-ADSyncConnector -Name "Contoso.com"
   

5. Execute the following script:

    New-ADSyncRule  `
    -Name 'Out to AD - Group SOAinAAD coexistence with Cloud Sync' `
    -Identifier '419fda18-75bb-4e23-b947-8b06e7246551' `
    -Description 'https://zcusa.951200.xyz/entra/identity/hybrid/cloud-sync/migrate-group-writeback' `
    -Direction 'Outbound' `
    -Precedence $outboundSyncRulePrecedence `
    -PrecedenceAfter '00000000-0000-0000-0000-000000000000' `
    -PrecedenceBefore '00000000-0000-0000-0000-000000000000' `
    -SourceObjectType 'group' `
    -TargetObjectType 'group' `
    -Connector $connectorAD.Identifier `
    -LinkType 'JoinNoFlow' `
    -SoftDeleteExpiryInterval 0 `
    -ImmutableTag '' `
    -OutVariable syncRule
   
    New-Object  `
    -TypeName 'Microsoft.IdentityManagement.PowerShell.ObjectModel.ScopeCondition' `
    -ArgumentList 'cloudNoFlow','true','EQUAL' `
    -OutVariable condition0
   
    Add-ADSyncScopeConditionGroup  `
    -SynchronizationRule $syncRule[0] `
    -ScopeConditions @($condition0[0]) `
    -OutVariable syncRule
   
    Add-ADSyncRule  `
    -SynchronizationRule $syncRule[0]
   
    Get-ADSyncRule  `
    -Identifier '419fda18-75bb-4e23-b947-8b06e7246551'
   

Step 5 - Use PowerShell to finish configuration

1. On your Microsoft Entra Connect server, open a PowerShell prompt as an administrator.

2. Import the ADSync module:

   Import-Module ADSync
   

3. Run a full sync cycle:

   Start-ADSyncSyncCycle -PolicyType Initial
   

4. Disable the group writeback feature for the tenant:

   Warning

   This operation is irreversible. After disabling group writeback V2, all Microsoft 365 groups will be written back to AD, independently of the Writeback Enabled setting in Entra admin center.

   Set-ADSyncAADCompanyFeature -GroupWritebackV2 $false 
   

5. Run a full sync cycle (yes again):

   Start-ADSyncSyncCycle -PolicyType Initial
   

6. Re-enable the sync scheduler:

   Set-ADSyncScheduler -SyncCycleEnabled $true  
   

   

Step 6 - Remove the Microsoft Entra Connect Sync server from staging mode

1. Start the Microsoft Entra Connect Sync wizard
2. Click Configure
3. Select Configure staging mode and click Next
4. Enter Microsoft Entra credentials
5. Remove the check from the Enable staging mode box and click Next
6. Click Configure
7. Click Exit

Step 7 - Configure Microsoft Entra Cloud Sync

Now that the groups are removed from the synchronization scope of Microsoft Entra Connect Sync, you can set up and configure Microsoft Entra Cloud Sync to take over synchronization of the security groups. See Provision groups to Active Directory using Microsoft Entra Cloud Sync.

Next Steps

• Provision groups to Active Directory using Microsoft Entra Cloud Sync
• Govern on-premises Active Directory based apps (Kerberos) using Microsoft Entra ID Governance
• Provisioning to Active Directory with Microsoft Entra Cloud Sync FAQ