The AlwaysOn Availability Groups feature requires the x86(non-Wow) or x64 Enterprise Edition of SQL Server 2012 (or later ...

The AlwaysOn Availability Groups feature requires the x86(non-Wow) or x64 Enterprise Edition of SQL Server 2012 (or later version) running on Windows Server 2008 (or later version) with WSFC hotfix KB 2494036 installed. This SQL Server edition and/or Windows Server system do not meet one or more of these requirements.

For more information about prerequisites, restrictions, and recommendations for AlwaysOn Availability Groups, see SQL Server Books Online.