Troubleshooting Azure AD Connect Synchronization Errors: A Step-by-Step Guide

Updated at: 12/06/2025

Azure AD Connect sync errors can disrupt your hybrid identity solution. This step-by-step guide provides practical solutions to common synchronization problems. Learn to diagnose issues like password hash synchronization failures, attribute mapping errors, and metaverse inconsistencies. We'll equip you with the troubleshooting skills to swiftly restore seamless user provisioning and access. Let's get started!

Step-by-Step Instructions

  1. Identify the Synchronization Error

    • Look for 'nostart Ma' at the import and 'stopped extension dll exception' at the export in the Microsoft connector.
    • Powershell might show an error related to MFA enrollment due to configuration changes or location changes.
    Check for MFA enrollment error: Powershell might show an error related to MFA enrollment due to configuration changes or location changes. Check for MFA enrollment error: Powershell might show an error related to MFA enrollment due to configuration changes or location changes.
    Identify the Synchronization Error

  2. Locate the Affected Synchronization Account

    • In Synchronization Service Manager, go to Connectors, select the Microsoft connector, then Properties > Connectivity to find the account used for synchronization.
    Identify the affected account: In Synchronization Service Manager, go to Connectors, select the Microsoft connector, then Properties > Connectivity to find the account used for synchronization.
    Locate the Affected Synchronization Account

  3. Analyze Azure Sign-in Logs

    • Look for failures with error code 5079 related to MFA configuration changes. This will reveal the affected account (sign-in identifier).
    Examine the sign-in logs in the Azure portal: Look for failures with error code 5079 related to MFA configuration changes. This will reveal the affected account (sign-in identifier).
    Analyze Azure Sign-in Logs

  4. Identify the Problematic Conditional Access Policy

    • Check the sign-in logs and Conditional Access tab to see which policy (e.g., 'CA all users MFA') caused the failure.
    Identify the Conditional Access policy: Check the sign-in logs and Conditional Access tab to see which policy (e.g., 'CA all users MFA') caused the failure.
    Identify the Problematic Conditional Access Policy

  5. Review Conditional Access Policy Details

    • Navigate to Security > Conditional Access to view the details of the identified policy. Verify that it requires multi-factor authentication and is applied to all users.
    Review Conditional Access Policy configuration: Navigate to Security > Conditional Access to view the details of the identified policy. Verify that it requires multi-factor authentication and is applied to all users.
    Review Conditional Access Policy Details

  6. Exclude Synchronization Account from Conditional Access Policy

    • In the Conditional Access policy's 'Assignments > Users and groups' section, select 'Exclude users and groups'. Search for the synchronization account and add it to the exclusions. Ensure that either the current user or an administrator is still included in the policy.
    Exclude the synchronization account from the Conditional Access Policy: In the Conditional Access policy's 'Assignments > Users and groups' section, select 'Exclude users and groups'. Search for the synchronization account and add it to the exclusions. Ensure that either the current user or an administrator is still included in the policy.
    Exclude Synchronization Account from Conditional Access Policy

  7. Initiate New Synchronization Cycle

    • After saving the changes, wait for the Conditional Access policy to update. Then, start a new synchronization cycle.
    Wait and initiate a new sync cycle: After saving the changes, wait for the Conditional Access policy to update. Then, start a new synchronization cycle.
    Initiate New Synchronization Cycle
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Tips

  • Carefully examine error messages to pinpoint the root cause. Pay close attention to error codes.
  • Always check the Azure AD sign-in logs for detailed information about authentication failures.

Common Mistakes to Avoid

1. Incorrect Password or Permissions

Reason: Azure AD Connect requires specific permissions and the correct credentials to connect to both your on-premises Active Directory and Azure AD. Incorrect credentials will prevent synchronization.
Solution: Verify the credentials used for both Active Directory and Azure AD, ensuring they have the necessary permissions.

2. Network Connectivity Issues

Reason: Azure AD Connect relies on network connectivity to both your on-premises Active Directory and Azure AD. Firewalls, network outages, or DNS resolution problems can disrupt synchronization.
Solution: Check network connectivity to both your on-premises Active Directory servers and Azure AD, ensuring that ports are open and DNS is correctly configured.

3. Attribute Mapping Errors

Reason: Incorrectly configured attribute mappings between on-premises Active Directory attributes and Azure AD attributes will lead to incomplete or incorrect user profiles in Azure AD.
Solution: Review and correct the attribute mappings in the Azure AD Connect Synchronization Rules Editor, ensuring data flows correctly between on-premises and cloud.

FAQs

Why is Azure AD Connect synchronization failing?
Synchronization failures can stem from various issues: network connectivity problems between your on-premises servers and Azure, incorrect configuration of AD Connect, password synchronization issues, attribute mapping errors, or problems with your on-premises Active Directory.
How can I troubleshoot password synchronization errors?
First, verify network connectivity and ensure the correct credentials are used. Check the event logs on both your on-premises servers and Azure AD Connect for specific error messages. Examine the password hash sync settings in Azure AD Connect and ensure they are properly configured. If using password writeback, check for any issues with the on-premises AD.
What should I do if I see a 'Connectivity' error in the Azure AD Connect Health dashboard?
A connectivity error typically indicates a network problem preventing communication between your on-premises environment and Azure. Check your firewall rules to ensure they allow communication on the necessary ports. Verify that your on-premises servers can reach Azure AD and that DNS resolution is working correctly. Also, check for any network outages or issues.