The 'Microsoft.ACE.OLEDB.12.0' provider is not registered on the local machine. (System.Data)

In case of the following error:

Download & Install "AccessDatabaseEngine_x64.exe" version of "Microsoft Access Database Engine 2010 Redistributable"  from following site:
http://www.microsoft.com/en-us/download/details.aspx?displaylang=en&id=13255

Attach DB error

In case of error try the following :

USE [master]
GO
CREATE DATABASE REAL_Warehouse_Sample_V6 ON
( FILENAME = N'D:\DB_MSSQL2012\REAL_Warehouse_Sample_V6.mdf' ),
( FILENAME = N'D:\DB_MSSQL2012\REAL_Warehouse_Sample_V6_log.LDF' )
FOR ATTACH
GO