SIRIS, ALTO, and NAS: Installing the Datto Windows Agent



This article describes the GUI-based installation process for the Datto Windows Agent.

For silent installation instructions, see Performing A Silent Install Of The Datto Windows Agent (Version 2.0) or Performing A Silent Install Of The Datto Windows Agent (Version 2.1 And Above).

For RMM deployment instructions, see Deploying the Datto Windows Agent (Version 2.0) via Datto RMM or Deploying the Datto Windows Agent (Version 2.1) via Datto RMM.


  • Datto Windows Agent (all versions)



This article assumes that you have reviewed both the SIRIS, ALTO And DNAS Networking & Bandwidth Requirements and the Getting Started with the Datto Windows Agent articles, and that your production environment meets the configurations described in both resources.

Pre-Deployment Requirements

If you have not done so already, to ensure an issue-free setup experience, review the Windows Pre-Deployment Configurations and Best Practices guide before proceeding.

Version 2.1 of the Datto Windows Agent requires Windows Vista, Windows Server 2008, or newer. The agent installer will automatically audit the operating system version of your protected machine. If it detects the presence of a legacy operating system, it will install the latest version of Datto Windows Agent 2.0 instead of the Datto Windows Agent 2.1 software.

Acronis software can prevent the installation of the Datto Windows Agent. For any machine that previously had an Acronis product installed, follow the steps in the Removing Acronis article to perform system cleanup.


Download the Agent Software

For Windows XP & Windows Server 2003

1. Download the agent software from the following link: Datto Windows Agent: Legacy Installer.

2. Proceed to the Setup section of this article.

For Windows Vista, Windows Server 2008, and Above

1. Download the agent software from the Datto Downloads page.

2. Navigate to and click the Windows icon in the Backup Agent Download category.

3. Proceed to the Setup section of this article.

Figure 1: Backup Agent Download (click to enlarge)


1. Launch the downloaded installer. You must have internet access both during the install and during the first start of the agent so that the software can retrieve certificates.

2. When the installer completes, you must reboot the production machine to finalize the installation of the agent.

3. If you are reinstalling the Datto Windows Agent after previously uninstalling it, use the Force a Differential Merge feature on your Datto appliance to queue a re-association of the backup increments for the protected system. If you do not schedule the protected system's next backup to be a differential merge, the first snapshot it captures following reinstallation of the Datto Windows Agent will be a full backup.

4. After you restart the production machine, pair the endpoint with your Datto appliance to begin taking backups.

Verifying the Installation

The Datto Windows Agent does not have a GUI. Follow these steps to confirm that the installation was successful:

  1. Make sure the production machine reboots following the installation of the Datto Windows Agent.
  2. Check Programs and Features to ensure that Datto Windows Agent appears as an installed program.
  3. Make sure that both essential services are present Datto Backup Agent Service and DattoProvider.

Installer Logging

The Datto Windows Agent includes installer logging. The logs generated by the installation process can help Technical Support troubleshoot common setup issues. See our Gathering Datto Windows Agent Installation Logs content for more information.

Technical Notes

Setting Schedules / Initial Configurations

Items to consider when configuring the Datto Windows Agent:

  • Before establishing a backup schedule, discuss with your client how far back they would ever need to go to retrieve data. Configure that agent's backup plan accordingly. Set the local data retention policies based on these conversations and expectations. Remember that long-running retention policies will require more disk space; consider this information when sizing an appliance.
  • Consider the server’s application: while a file server may need to be backed up during business hours as files are in constant change, a terminal server that houses configurations may not require as many backups per day as there is little to no change provided. Backups are just like any other service on a server; they consume resources and take disk input/output. Consider this while setting a schedule.
  • The size of your server's backups can grow if you use Distributed File System (DFS) in your environment. See How Distributed File System (DFS) Interacts with the Datto Solution for more information.
  • Before you take the first backup, make sure that you exclude any volumes that you do not want to be backed up. Remember that any additional drives that are attached to the machine may attempt to include themselves in the backup.
For information on other Datto backup configurations, see Configuring Alerts and SpeedSync.

Local File Creation

When you install the Datto Windows Agent, it creates a DattoCtrl (datto.ctl for DWA 2.1 agents) file and a DattoSnap (datto.snp for Datto Windows 2.1 endpoints) file on the protected server, in the root directory of each protected volume. You may need to select the Show hidden files and folders option or uncheck the Hide protected operating system files option in Windows to see them.

DattoCtrl (or Datto.ctl) generates at the start of the first backup, and it holds the space for the Copy On Write (COW) information during the backup.

Backup agents require sufficient space to track and block-transfer changes for subsequent backups. Each protected volume must meet the following 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% of the total size of the protected volume.
  • In all sizing scenarios, the agent software requires an additional 2 GB of free space.

To calculate the amount of space needed on your protected machine on a per-volume basis, use the size of the target volume and refer to the scenario matching your production environment. Refer to the Datto Windows Agent's storage space requirements for more information.

DattoSnap (or datto.snp) is the file that the Datto Windows Agent records changed block information so that it knows what it needs to move during each backup.

Additional Resources

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