Consider the following scenario:
You use AlwaysOn Availability Groups together with FileTables in an instance of Microsoft SQL Server 2012 or 2014.
You enable the FILESTREAM for file I/O access option on the replicas.
You restart a replica, and you set the replica as the primary replica after the restart.
In this scenario, the Filestream directory is not visible in Windows Explorer. However, you can still access the Filestream directory by using its full path.
For example, you can open a Filestream directory by using a full path similar to \\listener_name\mssqlserver\filetable_directory. However, if you browse to \\listener_name\mssqlserver, the filetable_directory folder is not visible.
The issue was first fixed in the following cumulative update or Service Pack for SQL Server.
Cumulative Update 3 for SQL Server 2012 Service Pack 3.
Service Pack 2 for SQL Server for SQL Server 2014
About Service packs for SQL Server
Service packs are cumulative. Each new service pack contains all the fixes that are in previous service packs, together with any new fixes. Our recommendation is to apply the latest service pack and the latest cumulative update for that service pack. You do not have to install a previous service pack before you install the latest service pack. Use Table 1 in the following article for finding more information about the latest service pack and latest cumulative update.
How to determine the version, edition and update level of SQL Server and its components
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Learn about the terminology that Microsoft uses to describe software updates.