SIRIS, ALTO, and NAS: ShadowSnap and Datto Windows Agent System Requirements for Windows-Based Backup Solutions



This article discusses minimum Windows system requirements for protecting servers with agent-based Datto backup solutions. For pre-deployment requirements, see Windows Pre-Deployment And Ongoing Server Requirements.

For agentless system requirements, see Getting Started with Agentless Backups.


  • Datto Windows Agent
  • ShadowSnap Agent


The Datto Windows Agent and the ShadowSnap backup agent protect Windows physical and virtual machines in conjunction with Datto's business continuity appliances.


Compatibility of this backup solution with any hypervisor environment or operating system not listed in this article is untested and may yield unreliable results.

Supported Operating Systems

All operating systems shown include 32-bit and 64-bit versions.

Except where noted, all operating systems listed are compatible with the Datto Windows Agent, ShadowSnap Agent, and Datto's Agentless solution.

  • Windows XP (note: Microsoft no longer issues keys for Windows XP: you may not be able to re-activate installations that use OEM keys)
  • Windows Server 2003 (note: Microsoft no longer issues keys for Windows Server 2003: you may not be able to re-activate installations that use OEM keys)
  • Windows Vista
  • Windows Server 2008 / R2
    • Includes Windows Small Business Server 2011
  • Windows 7
  • Windows 8 / 8.1
  • Windows 10
  • Windows Server 2012 / R2
  • Windows Server 2016 (Datto Windows Agent and agentless only)
  • Windows Server 2019 (Datto Windows Agent and agentless only)
Datto supports software RAID for backups, virtualizations, and file restores, but software RAID is not compatible with the Datto Utilities Bare Metal Restore process.

Dual-boot environments

Datto supports any of the above Windows installations running on Apple hardware via Boot Camp for backup, virtualization, image export, and file restore. Due to dual-boot environment limitations, Datto does not support Bare Metal Restore on dual boot systems and only the Windows partition on Boot Camp installations will be backed up.

Supported Disk Volume Types

  • Basic volumes and disks.
  • Windows dynamic disks.
    If a dynamic disk expands, the next backup will be a differential merge. Frequent differential merges can delay your backup schedule and will increase the time that agents are consuming system resources.
  • NTFS filesystems (Datto Windows Agent and ShadowSnap Agent)
  • ReFS filesystems (Datto Windows Agent only, Version 2.1 or above)
    • FAT32 file systems are currently unsupported.
  • Hardware and software-based RAID implementations.
  • Any size disk drive, including disks larger than 2TB in size.
  • MBR boot sectors and GPT partition tables.
  • Virtual & physical disks:
    • The Datto solution is capable of backing up multiple types of disk sector schemes. The process writes an image-based backup to a file which is 512 bytes per physical sector. While rare, certain software which 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 environments.
All protected volumes must be Read/Write. Read-Only volumes cannot be backed up.

Deduplication Warnings

  • Backup of deduplicated volumes is untested and may produce inconsistent results.
  • File restore of deduplicated volumes is not possible. The Datto Windows Agent, ShadowSnap Agent, and agentless backup solutions are capable of restoring deduplicated volumes through:

Web Browser

Datto tests the appliance's GUI with the Mozilla Firefox and Google Chrome web browsers. Using Microsoft Internet Explorer or Microsoft Edge may compromise functionality.

Network Requirements

Review the SIRIS, ALTO, and NAS Networking & Bandwidth Requirements article to ensure that your systems are ready to install the backup agent.

Minimum Resource Requirement

Datto recommends a minimum of 1 GB of free RAM for the backup agent. If the agent is reporting errors with less than 1 GB of RAM available, the production machine may require performance tuning or additional resources.

Available Space of Each Protected Volume

Available space requirements vary by agent type.

ShadowSnap Agent Only

Datto recommends maintaining at least 30% free space per protected volume. A minimum of 20% free space per protected volume must be available at all times on the production machine.

Volume Utilization



0 – 70%


Utilization is good.

71 – 80%


Utilization is outside optimal limits. Monitor the volume growth and look at cleaning up unnecessary files and moving non-essential data to other storage.

81 – 100%


Volume is becoming critical. Snapshots will start to fail. Disk queue lengths will increase. Create space.

Shadow Copies

The Datto backup solution relies on shadow storage on the protected machine to complete the backup process successfully. Make sure to disable Shadow Copy processes that are not Datto-related, as these can conflict with Datto backups. For more information, see Disabling and Purging Shadow Copies On Windows Servers.

Additional Resources

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