56493: Acronis Backup Cloud and Acronis Backup 12: how to preserve original machine ID when re-adding deleted machine

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Operating Systems: 

Every time an Agent is installed, a new entity is created in Acronis software and the machine is displayed in the Backup management console. When the Agent is reinstalled, a second entry might appear for the same machine and new backup archives for this machine will be created once old backup plans are applied. To prevent these duplicates from appearing, leave Remove the logs and configuration settings (Windows) or Clean up all product traces (Linux) cleared.

This article describes the alternative way to register machine in Acronis Management Server and to continue backing up to old archives.


Every time an Agent is installed, the machine receives unique parameters - MMSCurrentMachineID and InstanceID.

In order to preserve the original MMSCurrentMachineID and InstanceID when reinstalling the Agent proceed according to the steps below:

1. Note the original MMSCurrentMachineID and InstanceID:

  • either in Windows Registry on the machine these parameters are stored in the HKLM\Software\Acronis\BackupAndRecovery\Settings\MachineManager registry key.
  • or in the browser address bar while selecting the machine in backup management console. GUID between "phm." and "%40" is InstanceID, after "%40" is MMSCurrentMachineID:

2. Make sure that machine is not present in the Backup management console. In case it is - delete it.

3. If the Agent is still installed on the machine, proceed to next step. If not, it is necessary to install the Agent without registering machine in the Management Server:

- Download the Backup Client's installation file from the Backup management console.

- Open command prompt as Administrator, navigate to the folder you've saved installation file to

- Start installation running the following command:

Backup_Agent_for_Windows_web.exe /skip-registration

4. Once the Agent is installed, change values of MMSCurrentMachineID and InstanceID to the original ones:

In Windows: start Windows registry editor (Start -> Search -> regedit.exe) and navigate to the following key: HKLM\Software\Acronis\BackupAndRecovery\Settings\MachineManager

In Linux: open /etc/Acronis/BackupAndRecovery.config and modify these values:
     <value name="InstanceID" type="TString">
                        <value name="MMSCurrentMachineID" type="TString">

On Mac: open /Library/Application Support/Acronis/Registry/BackupAndRecovery.config and modify these values:
     <value name="InstanceID" type="TString">
                        <value name="MMSCurrentMachineID" type="TString">

5. Register machine manually according to this KB article (Acronis Backup 12) or this KB article (Acronis Backup Cloud).

6. Log in to the Backup management console and check whether the machine has appeared. Apply original backup plan(s) to the machine.

More information

This method can be used to preserve original file-level backup plans in case of machine replacement and Agent reinstallation on the new machine:

  1. You have been creating file-level backups with Acronis backup software.
  2. You are about to decommission the machine, replace the machine with a new one, reinstall the operating system, or restore your machine from an existing backup you have created with another vendor's backup software.
  3. You want to restore files to the new machine and continue backing up.

In this case you need to restore from your file-level backups, and then proceed as described in the Solution part above.