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This article describes the improvements and issues that are fixed in the Azure File Sync Agent v5 release that is dated February 2019. Additionally, this article contains installation instructions for this release.

Improvements and issues that are fixed

  • Support for Azure Government cloud

    • We have added preview support for the Azure Government cloud. This requires a white-listed subscription and a special agent download from Microsoft. To get access to the preview, please email us directly at

  • Support for Data Deduplication

    • Data Deduplication is now fully supported with cloud tiering enabled on Windows Server 2016 and Windows Server 2019. Enabling deduplication on a volume with cloud tiering enabled lets you cache more files on-premises without provisioning more storage.

  • Support for offline data transfer (e.g. via Data Box)

    • Easily migrate large amounts of data into Azure File Sync via any means you choose. You can choose Azure Data Box, AzCopy and even third party migration services. No need to use massive amounts of bandwidth to get your data into Azure, in the case of Data Box – simply mail it there! To learn more, see Offline Data Transfer Docs.

  • Improved sync performance

    • Customers with multiple server endpoints on the same volume may have experienced slow sync performance prior to this release. Azure File Sync creates a temporary VSS snapshot once a day on the server to sync files that have open handles. Sync now supports multiple server endpoints syncing on a volume when a VSS sync session is active. No more waiting for a VSS sync session to complete so sync can resume on other server endpoints on the volume.

  • Improved monitoring in the portal

    • Charts have been added in the Storage Sync Service portal to view:

      • Number of files synced

      • Size of data transferred

      • Number of files not syncing

      • Size of data recalled

      • Server connectivity status

    • To learn more, see Monitor Azure File Sync.

  • Improved scalability and reliability

    • Maximum number of file system objects (directories and files) in a directory has increased to 1,000,000. Previous limit was 200,000.

    • Sync will try to resume data transfer rather than retransmitting when a transfer is interrupted for large files

More information about the Azure File Sync Agent v5 release

  • The Azure File Sync agent is supported on Windows Server 2012 R2, Windows Server 2016, and Windows Server 2019.

  • Azure File Sync agent version or a later version is required to upgrade existing agent installations.

  • A restart may be required if files are in use during the installation.

  • The agent version for the v5 release is

How to obtain and install the Azure File Sync Agent

The Azure File Sync agent is available from Microsoft Update, Microsoft Update Catalog, and Microsoft Download Center.


  • If the Azure File Sync agent is not currently installed on a server, use the agent installation package on the Microsoft Download Center. The agent installation package on Microsoft Update and Microsoft Update Catalog is intended for agent upgrades only.

  • To update existing agent installations, run AfsUpdater.exe (located in the agent installation directory) or download and install the update from Microsoft Update or Microsoft Update Catalog.

Microsoft Update

To obtain and install from Microsoft Update, follow these steps on a server that has Azure File Sync agent installed:

Server 2016and Server 2019

  1. Click Start, and then click Settings.

  2. In Settings, click Update & security.

  3. In the Windows Update window, click Check online for updates from Microsoft Update.

  4. Verify the update is listed and then click Install now.

Server 2012 R2

  1. Click Start, and then click Control Panel.

  2. In Control Panel, double-click Windows Update.

  3. In the Windows Update window, click Check for updates.

  4. Click Important updates are available.

  5. Verify the update is selected, and then click Install.

Microsoft Update Catalog

Go to the following website to manually download this update from the Microsoft Update Catalog:

Azure File Sync Agent v5 release: February 2019 (KB4459989)

To manually install the update package, run the following command from an elevated command prompt:

  • msiexec.exe /p packagename.msp REINSTALLMODE=OMUS REINSTALL=StorageSyncAgent,StorageSyncAgentAzureFileSync,StorageSyncAgentGuardFilter,StorageSyncAgentUpdater /qb /l*v KB4459989.log

For example, to install the Azure File Sync agent update for Server 2016, run the following command:

  • msiexec.exe /p StorageSyncAgent_WS2016_KB4459989.msp REINSTALLMODE=OMUS REINSTALL=StorageSyncAgent,StorageSyncAgentAzureFileSync,StorageSyncAgentGuardFilter,StorageSyncAgentUpdater /qb /l*v KB4459989.log

Microsoft Download Center

Go to the Microsoft Download Center to manually download the full installer release of Azure File Sync Agent v5 release.

How to perform a silent installation for a new agent installation

To perform a silent installation for a new agent installation that uses the default settings, run the following command at an elevated command prompt:

  • msiexec /i packagename.msi /qb /l*v AFSv5Installer.log

For example, to install the Azure File Sync agent for Windows Server 2016, run the following command: 

  • msiexec /i StorageSyncAgent_V5_WS2016.msi /qb /l*v AFSv5Installer.log 

Note Use the /qb switch to display restart prompts (if required), agent update, and server registration screens. To suppress the screens and automatically restart the server (if required), use the /qn switch.

Note: To perform a silent installation with custom settings, follow the steps documented in KB4459986.

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