This article describes the improvements and issues that are fixed in the Azure File Sync Agent v13 release that is dated July 2021. Additionally, this article contains installation instructions for this release.

Improvements and issues that are fixed

Authoritative upload

Authoritative upload is a new mode available when creating the first server endpoint in a sync group. It is useful for the scenario where the cloud (Azure file share) has some/most of the data but is outdated and needs to be caught up with the more recent data on the new server endpoint. This is the case in offline migration scenarios like DataBox, for instance. When a DataBox is filled and sent to Azure, the users of the local server will keep changing / adding / deleting files on the local server. That makes the data in the DataBox and thus the Azure file share, slightly outdated. With Authoritative Upload, you can now tell the server and cloud, how to resolve this case and get the cloud seamlessly updated with the latest changes on the server.

No matter how the data got to the cloud, this mode can update the Azure file share if the data stems from the matching location on the server. Be sure to avoid large directory restructures between the initial copy to the cloud and catching up with Authoritative Upload. This will ensure you are only transporting updates. Changes to directory names will cause all files in these renamed directories to be uploaded again. This functionality is comparable to semantics of RoboCopy /MIR = mirror source to target, including removing files on the target that no longer exist on the source.

Authoritative Upload replaces the "Offline Data Transfer" feature for DataBox integration with Azure File Sync via a staging share. A staging share is no longer required to use DataBox. New Offline Data Transfer jobs can no longer be started with the AFS V13 agent. Existing jobs on a server will continue even with the upgrade to agent version 13.

Portal improvements to view cloud change enumeration and sync progress

When a new sync group is created, any connected server endpoint can only begin sync, when cloud change enumeration is complete.  In case files already exist in the cloud endpoint (Azure file share) of this sync group, change enumeration of content in the cloud can take some time. The more items (files and folders) exist in the namespace, the longer this process can take. Admins will now be able to obtain cloud change enumeration progress in the Azure portal to estimate an eta for completion / sync to start with servers.

Support for server rename

If a registered server is renamed, Azure File Sync will now show the new server name in the portal. If the server was renamed prior to the v13 release, the server name in the portal will now be updated to show the correct server name.

Support for Windows Server 2022

The Azure File Sync agent is now supported on Windows Server 2022. 

Note: Windows Server 2022 adds support for TLS 1.3 which is not currently supported by Azure File Sync.  If the TLS settings are managed via group policy, the server must be configured to support TLS 1.2.

Miscellaneous improvements

  • Reliability improvements for sync, cloud tiering and cloud change enumeration.

  • If a large number of files is changed on the server, sync upload is now performed from a VSS snapshot which reduces per-item errors and sync session failures.

  • The Invoke-StorageSyncFileRecall cmdlet will now recall all tiered files associated with a server endpoint, even if the file has moved outside the server endpoint location.

  • Explorer.exe is now excluded from cloud tiering last access time tracking.

  • New telemetry (Event ID 6664) to monitor the orphaned tiered files cleanup progress after removing a server endpoint with cloud tiering enabled.

More information about the Azure File Sync Agent v13 release

  • This release is available for Windows Server 2012 R2, Windows Server 2016, Windows Server 2019 and Windows Server 2022 installations.

  • A restart is required for servers that have an existing Azure File Sync agent installation if the agent version is less than version 12.0.

  • The agent version for this 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 2016 and 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 Azure File Sync agent 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 Azure File Sync agent 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 v13 release: July 2021 (KB4588753)

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 KB4588753.log

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

msiexec.exe /p StorageSyncAgent_WS2016_KB4588753.msp REINSTALLMODE=OMUS REINSTALL=StorageSyncAgent,StorageSyncAgentAzureFileSync,StorageSyncAgentGuardFilter,StorageSyncAgentUpdater /qb /l*v KB4588753.log

Microsoft Download Center

Go to the Microsoft Download Center to manually download the agent installation package for new agent installations.

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 AFSv13Installation.log

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

msiexec /i StorageSyncAgent_WS2016.msi /qb /l*v AFSv13Installation.log


  • 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.

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

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