Azure not syncing O365 from On prem

Anonymous
2026-02-27T19:06:45.1+00:00

Office 365 is telling me my on premise server is not syncing. I tried updating Azure but it fails.

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  1. AI answer

    2026-02-27T19:06:56.9066667+00:00

    Directory synchronization issues between an on-premises Active Directory and Microsoft 365 are commonly caused by problems with the synchronization tool or its connectivity.

    Start with these checks and fixes:

    1. Confirm which sync tool is in use
      • If the environment is still using the legacy Microsoft Online Services Directory Synchronization tool (DirSync / Azure AD Sync), it is deprecated and no longer accepted by Microsoft Entra ID.
      • In this case, synchronization will stop and events like ID 0 or 109 appear stating the tool is no longer supported.
    2. If using the old DirSync/Azure AD Sync tool, upgrade to Microsoft Entra Connect
      • Uninstall the deprecated Microsoft Online Services Directory Sync tool from the server.
      • Install Microsoft Entra Connect on a supported 64-bit Windows Server.
      • From the Microsoft 365 admin center, go to Users → Active users → More (…) → Directory synchronization and follow the wizard to download and set up Microsoft Entra Connect.
      • For existing DirSync/Azure AD Sync deployments, follow the documented upgrade path to Microsoft Entra Connect.
    3. If already using Microsoft Entra Connect but sync is reported as not recent
      • Use the guidance under “I have an alert in the admin center, or am receiving automated emails that there hasn't been a recent synchronization event” to troubleshoot:
        • Check connectivity from the Entra Connect server to Microsoft 365 and Microsoft Entra ID.
        • Verify the Entra Connect service account and permissions.
        • Review the Entra Connect health and logs using the connectivity troubleshooting guidance.
    4. Verify directory sync status in Microsoft 365
      • In the Microsoft 365 admin center, check the DirSync/Directory Sync status tile and any error details.
      • If there are specific sync error reports (for example, duplicate attributes, object quota exceeded, or password hash sync alerts), use the corresponding troubleshooting articles linked from the directory synchronization problems page.

    If synchronization still fails after upgrading to Microsoft Entra Connect and confirming connectivity and permissions, use the referenced troubleshooting articles for detailed step-by-step diagnostics, or open a support request from the Microsoft 365 admin center.

    References:

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