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MARS OBEngine not found following corrupt installation

Steve Jarvis - S50 Managed IT 0 Reputation points
2026-05-25T06:28:51.97+00:00

Need the legacy MSI-based Microsoft Azure Recovery Services (MARS) Agent installer.

The current unified 72 MB installer fails to deploy OBEngine and OBService components.

Need the April 2025 MSI bundle for manual installation after a corrupt installation/uninstall as backup failing with OBEngine failure error

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  1. Suchitra Suregaunkar 14,435 Reputation points Microsoft External Staff Moderator
    2026-05-25T11:08:37.8633333+00:00

    Hello Steve Jarvis - S50 Managed IT

    Thank you for posting you query on Microsoft Q&A platform.

    Microsoft does not publish a separate legacy MSI-based MARS agent installer. The only officially supported installer is the unified MARSAgentInstaller.exe (~72 MB), which you can download from here: https://aka.ms/azurebackup_agent

    That said, when the unified installer fails to deploy OBEngine and OBService components due to a corrupt prior installation, there is an officially documented workaround to extract and manually apply the MSI. This is documented in the following Microsoft KB article:

    The Microsoft Azure Recovery Services Agent update failed

    Here's what you can do:

    Step 1 – Clean up the previous installation

    • Go to Programs and Features (appwiz.cpl) and uninstall Microsoft Azure Recovery Services Agent if it still appears.
    • Delete any residual files under C:\Program Files\Microsoft Azure Recovery Services Agent\.
    • Reboot the machine.

    Step 2 – Download the latest MARS agent

    Step 3 – Extract the MSI from the installer

    • Double-click the downloaded MARSAgentInstaller.exe — this copies all setup binaries (including the MSI) to a temp location and opens the upgrade wizard.
    • Leave the wizard open — do not close it.
    • Open C:\Windows\Temp\OBInstaller0Curr.errlog, search for "Directory Path for SetupLaunchScreen" and note the temp path (e.g., C:\<Temp_ID>).
    • Navigate to C:\<Temp_ID>\Installers\ — you will find OBSAGENT.msi there.

    Step 4 – Install the MSI manually Run from an elevated command prompt:

    msiexec /i "C:\<Temp_ID>\Installers\OBSAGENT.msi"

    Step 5 – Complete the installation After the MSI installs successfully, close the wizard and run the full MARSAgentInstaller.exe again to complete the setup (registration, configuration, etc.).

    Step 6 – Verify OBEngine is running Open PowerShell and run:

    Get-Service -Name "obengine"

    The service should show as Running.

    For additional MARS agent troubleshooting, please refer to:

    Hope this helps! Please let us know if you have any further questions.

    Thanks,
    Suchitra.

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  2. AI answer

    2026-05-25T06:29:08.1833333+00:00

    The context does not provide an April 2025 legacy MSI bundle or any direct download link for a separate OBEngine/OBService installer. It only provides guidance to fix OBEngine-related issues by upgrading the MARS agent to a supported version and, where relevant, addressing known causes of OBEngine failures.

    From the available information, the supported remediation path for OBEngine-related failures after a corrupt installation/uninstallation is:

    1. Install a supported MARS agent version that includes OBEngine
      • For older environments affected by the specific OBEngine connection error when adding the MARS snap‑in, install MARS Agent version 2.0.9072.0 from the Microsoft Download Center as described in the KB article. This version replaces earlier problematic builds (2.0.9070.0 and 2.0.9071.0) and fixes the error:
        • Error: The Microsoft Recovery Services Agent cannot connect to the OBEngine service. Verify that the OBEngine service is present in the Services Control Panel and that port 6049 is available.
      • The KB explicitly states this update is mandatory and that it contains the fix for the OBEngine connectivity issue.
    2. Ensure Data Protection Manager (if used) is at the required update level
      • If System Center Data Protection Manager (DPM) is in use with MARS, the KB requires:
        • System Center 2016 DPM: Update Rollup 1 or later.
        • System Center 2012 R2 DPM: Update Rollup 11 or later.
      • These are prerequisites for applying the MARS 2.0.9072.0 update.
    3. Restart requirements
      • If running Windows Server 2008 (SP2 or R2 SP1), a restart is required after applying the update.
      • Other Windows Server versions do not require a restart per the KB.
    4. For general OBEngine connection failures during backup
      • The troubleshooting guidance for MARS indicates that backup failures with:
        • Error code: Cannot connect to CBEngine
        • Error message: The Microsoft Azure Recovery Services Agent cannot connect to the OBEngine service.
      • Common cause: OBEngine service crash, often due to an incompatible Azure File Sync Agent (StorageSync.sys driver) on the same machine.
      • Recommended action in that scenario is to disable the StorageSync.sys driver and then retry the backup.
    5. Keep MARS agent on a supported, current build
      • The support matrix and troubleshooting guidance recommend using recent MARS versions (for example, 2.0.9249.0 or higher for vault registration, and 2.0.9250.0 or higher for offline seeding with Azure Data Box APIs) rather than older agents.
      • For version mismatches between Azure Backup service and MARS agent, the documented resolution is to download and install the latest Azure Backup Agent and let the upgrade wizard repair/upgrade the existing installation.

    The context does not expose any separate MSI for OBEngine/OBService or an April 2025 MSI bundle. The only supported and documented approach is to repair the environment by installing a supported full MARS agent build (such as 2.0.9072.0 in the specific OBEngine KB, or the latest agent from the Azure Backup documentation) and addressing any conflicting drivers or version prerequisites.

    References:

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