Data Source Names and 64-Bit Operating Systems
SQL Server Native Client (SNAC) is not supported beyond SQL Server 2012. Avoid using SNAC in new development work, and plan to modify applications that currently use it. The Microsoft ODBC Driver for SQL Server provides native connectivity from Windows to Microsoft SQL Server and Microsoft Azure SQL Database.
To build and run an application as a 32-bit application on a 64-bit operating system, you must create the ODBC data source with the ODBC Administrator in %windir%\SysWOW64\odbcad32.exe.
A 64-bit Windows operating system has two odbcad32.exe files:
%SystemRoot%\system32\odbcad32.exe is used to create and maintain data source names for 64-bit applications.
%SystemRoot%\SysWOW64\odbcad32.exe is used to create and maintain data source names for 32-bit applications, including 32-bit applications that run on 64-bit operating systems.