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This article describes the improvements and issues that are fixed in the Azure File Sync Agent v12 release that is dated March 2021. Additionally, this article contains installation instructions for this release.

Improvements and issues that are fixed

New portal experience to configure network access policy and private endpoint connections

You can now use the portal to disable access to the Storage Sync Service public endpoint and to approve, reject and remove private endpoint connections. To configure the network access policy and private endpoint connections, open the Storage Sync Service portal, go to the Settings section and click Network.

Cloud Tiering support for volume cluster sizes larger than 64KiB

Cloud Tiering now supports volume cluster sizes up to 2MiB on Server 2019. To learn more, see What is the minimum file size for a file to tier?.

Measure bandwidth and latency to Azure File Sync service and storage account

The Test-StorageSyncNetworkConnectivity cmdlet can now be used to measure latency and bandwidth to the Azure File Sync service and storage account. Latency to the Azure File Sync service and storage account is measured by default when running the cmdlet.  Upload and download bandwidth to the storage account is measured when using the "-MeasureBandwidth" parameter.

For example, to measure bandwidth and latency to the Azure File Sync service and storage account, run the following PowerShell commands:

Import-Module "C:\Program Files\Azure\StorageSyncAgent\StorageSync.Management.ServerCmdlets.dll"

Test-StorageSyncNetworkConnectivity -MeasureBandwidth

Improved error messages in the portal when server endpoint creation fails

We heard your feedback and have improved the error messages and guidance when server endpoint creation fails.

Miscellaneous performance and reliability improvements

  • Improved change detection performance to detect files that have changed in the Azure file share.

  • Performance improvements for reconciliation sync sessions.


  • Fixed a bug that causes data corruption if cloud tiering is enabled and tiered files are copied using Robocopy with the /B parameter.

  • Fixed a bug that can cause files to fail to tier on Server 2019 if Data Deduplication is enabled on the volume.

  • Fixed a bug that can cause AFSDiag to fail to compress files if a file is larger than 2GiB.

More information about the Azure File Sync Agent v12 release

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

  • A restart is required for servers that have an existing Azure File Sync agent installation.

  • The agent version for this release is

How to obtain and install the Azure File Sync Agent 

The Azure File Sync v12 release is no longer available due to an agent auto-update issue that was identified.

Note: If the v12 release is already installed on your servers, the agent auto-update feature will fail to update the agent to a later version. To update the agent to a later version (once available), you will need to manually install the agent update from the Microsoft Update Catalog or wait until the agent update is available on Microsoft Update.

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