SIRIS, ALTO, and NAS: Getting started with the Datto Windows Agent



This article describes system requirements for the Datto Windows Agent.  


  • Datto Windows Agent


System requirements   


Datto Windows Agent 1.0 and 2.0

  • Windows XP Service Pack 3
  • Windows Storage Server 2003
  • Windows Server 2003 Service Pack 2
  • Windows Vista

Datto Windows Agent 2.1 and above

  • Windows Server 2008 Service Pack 2
  • Windows Server 2008 R2 Service Pack 1 and later 
    • Includes Windows Small Business Server 2011)

*See this KB article for important update information before installing on Windows 2008 R2 SP1

  • Windows 7 Service Pack 1
  • Windows 8
  • Windows 8.1
  • Windows 10
  • Windows Server 2012
  • Windows Server 2016
  • Windows Server 2019
Supported disk types
  • Hardware and software-based RAID implementations are supported.
  • Any size disk drive can be backed up, including disks larger than 2TB.
  • MBR boot sectors and GPT partition tables.
  • Virtual & physical disks.
  • Basic volumes and disks.
  • Windows dynamic disks. 
  • Protected volumes must be Read/Write. You cannot back up Read-Only volumes.
Disk space requirements
  • The Datto Windows Agent needs each volume selected for backup to have 10% of the volume's total size available for the DattoCtrl or Datto.ctl file except in the following scenarios:
    • For versions 2.0 and below of the Datto Windows Agent, if the volume is large enough that 10 GB is less than 10% of the total disk space, the agent will use the percentage of the volume's size that is closest to and is at least 10 GB. For example, for a 560 GB volume, the COW file size will be 2% of the volume and be about 11.2 GB in size.
    • For versions 2.1 and above of the Datto Windows Agent, if the 10% number is larger than 10 GB, the file's size will be 10 GB, regardless of the total size of the protected volume.
  •  In all sizing scenarios, the agent requires an additional 2 GB of free space for operational overhead.
CPU and Memory requirements
  • At least 1 GB of RAM must remain free during normal operations of the production machine for install and backups to run.
  • Datto recommends a minimum of 2 CPU cores for the backup agent, depending on workloads. If the agent is experiencing high CPU usage during backups with fewer than 2 CPUs, the production machine may require additional resources.
  • Gigabit connections from the Datto appliance to all appropriate network infrastructure. For best results, the Datto appliance should be connected to a gigabit switch whenever possible.
  • The protected machine must have Internet access and be able to reach for the initial installation and ongoing operation of the Datto Windows Agent.
  • Outbound connectivity on the protected machine:
    • Port 443 (for Datto Cloud communication)
    • Port 3260 (for iSCSI)
    • Port 3262 (for MercuryFTP)
  • Inbound connectivity on the protected machine:
    • TCP port 25568 (for Datto Windows Agent service)
  • Outbound from the Datto appliance to the Internet:
    • Ports 22, 80, 123, 443
  • Bypass any local proxy to (, on port 443 for correct certificate installation during DWA install.
  • The Datto Windows Agent uses MercuryFTP as its primary transport method; however, if this method fails, backups are intended to fall back to iSCSI.
  • For an in-depth overview of Datto's networking requirements, see the SIRIS, ALTO, and DNAS Networking & Bandwidth Requirements article.
Anti-virus exceptions
  • Set service-level exceptions for the Datto Backup Agent and Datto Provider services.
  • Set an application-level exception for the Datto Windows agent (DattoBackupAgent.exe).
  • Whitelist the following installation path: %PROGRAMFILES%\Datto\
  • The production machine must use a ReFS or NTFS filesystem.
  • Acronis True Image and Acronis Disk Director are incompatible with the Datto Windows Agent. Ensure that neither product is present on the protected system before attempting to install the Datto Windows Agent.
  • FAT32 filesystems are currently unsupported.
  • French versions of Windows older than Windows Server 2008 are unsupported by the Datto Windows Agent.
  • The compatibility of this backup solution with any hypervisor environment or operating system not listed in this article is untested and may yield unreliable results.


You can download the latest version of the Datto Windows Agent from the Datto Downloads page.

Version numbers for all Datto Windows Agent endpoints protected by your Datto device appear on the appliance's Device Overview page, in the Local Agent Information field, under the Agent Version heading for each listed production machine.

For Windows XP & Windows Server 2003

The current version of the Datto Windows Agent is, For release notes, refer to the Datto Windows Agent (DWA) 1.0 and 2.0: Release notes.

You can download this version of the agent software from the following link: Datto Windows Agent: Legacy Installer.

For Windows Vista, Windows Server 2008, and above

Version information for this platform of the Datto Windows Agent is available in the Datto Windows Agent (DWA) Version 2.1 and above: Release notes.

Datto Windows Agent Version 2.2 was a significant upgrade. This release included new drivers, which means that older existing agent installations will not automatically updateTo update your agent software to the latest DWA version, follow the steps in our Updating to Datto Windows Agent Version 2.2 and above article.

Update notes for all versions

The agent software automatically updates itself when a new version becomes available, except when the release includes a driver update. Because a driver update requires an update and reboot of the host system, these updates are not automatically downloaded. You will need to manually download and install these versions yourself.

The Datto Windows Agent will attempt to connect with Datto' servers to check for updates on a daily basis. If your protected machine does not have regular internet access, you will need to check for and install updates manually.


When you install the Datto Windows Agent, you are installing the following services on your Windows machine.

  • Datto Backup Agent Service:  This is the primary service for the webserver, backup jobs, logging, and operation.
  • DattoProvider:  This is the driver that handles the backup engine and VSS interaction. This service is required to quiesce the operating system and take a block-level backup.


Figure 1 illustrates a generalized data flow for the Datto Windows Agent solution.

flow__1_.pngFigure 1: Data flow for the Datto Windows Agent (click to enlarge)

For a technical overview of the Datto Windows Agent, see One Take: A Look at the Datto Windows Agent.


Compatibility of this backup solution with any hypervisor environment or operating system not listed in this article is untested and may yield unreliable results. Universal VM Backup may be a viable alternative for backing up virtual machines with operating systems that are not listed as compatible.
  • Due to their mobile nature, Datto does not endorse or support backing up laptops. Laptops must be inside the LAN, and not on a wireless network, to perform backups promptly. Attempts to back up laptops are at your discretion. Due to the range of touchpad drivers, custom drivers, and hardware configurations available for both laptops and all-in-one workstations, restoration support for these platforms is 'best-effort' only.
  • The Datto Windows Agent can only back up volumes that are recognized by the Windows operating system as logical, stable volumes. It cannot back up mapped network drives, iSCSI targets not attached as a logical volume, or removable drives.
  • The Datto solution is capable of backing up multiple types of disk sector schemes. The process writes an image-based backup to a file that is 512 bytes per physical sector. While rare, some software that relies on advanced formats, such as 4K, may have issues with the sector size change. Datto recommends performing regular DR tests to ensure that all required applications function as expected in our virtualized environment.
  • Backup of deduplicated volumes is untested and may produce inconsistent results. 
  • File restore of deduplicated volumes is not possible. While it may be technically possible to restore deduplicated volumes through virtualizationDirect Restore, or Bare Metal Restore, this is untested and may produce inconsistent results. 


Datto recommends running the following checks on the system you are protecting before installing the Datto Windows Agent:


Run chkdsk to be sure that all RAIDs and individual disks report back as healthy. Perform necessary disk repairs before deploying any backup agent. Failure to do so may result in backing up corrupted systems and restoration failures.

Disk defragmentation

  • While Datto can perform backups that are running disk defragmentation, be aware that this rearranges data at a block level, and may result in larger backups.
  • Run disk defragmentation before you deploy the agent. 
  • VSS-aware disk defragmentation programs may allow for smaller backups but are optional.

Windows updates

Download Windows updates, service packs, and any other Microsoft provided updates. After installing these updates, reboot the server. When scheduling your deployment, remember that the 2nd Tuesday of every month is Microsoft's 'Patch Tuesday.'

Virus scan

Run a virus scan before you deploy the Datto backup solution to your production machine.

Event Viewer 

  • Check the target's system and application logs to see if there are any VSS or hardware errors.
  • Resolve any errors before attempting to install the agent.
  • Do not install the Datto Windows Agent on any system currently protected by the ShadowSnap Agent, even if the ShadowSnap Agent is not present. Installing the Datto Windows Agent will start a new backup chain for the protected system and will not continue your existing ShadowSnap chain.
  • Before installing the Datto Windows Agent, disable or remove all other backup software from the production machine. When uninstalling, use a high-level program that eliminates all traces of the incompatible software, including registry keys, DLLs, and stray folders. These components can cause conflicts.

Group Policy

  • To avoid issues with installing the necessary certificates, ensure that the Windows Group Policy is not set to "Allow only Enterprise Administrators"

See Installing the Datto Windows Agent to learn how to deploy the agent to your production machine.

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