The database 'AdventureWorks2012' cannot be opened because it is version 705. This server supports version 655 and earlier. A downgrade path is not supported.
Could not open new database 'AdventureWorks2012'. CREATE DATABASE is aborted. (.Net SqlClient Data Provider)
It seemed to be a rather silly mistake where I had copied the .mdf for Adventure Works 2012 in a SQL Express 2010 folder. Here’s the set up screenshot on my machine
Instead of copying the .mdf to MSSQL11.SQLEXPR12 (which is the folder setup for SQL Express 2012), I had copied it to the MSQL10 folder.
The fix was simple, I copied the file to the correct folder, ran SQL Management Studio as administrator and bingo! The error went away!