How to downgrade my mdf file from version 661 to 655 or earlier? I have a problem when attaching the file AdverntureWorksLT2008R2_Data.mdf to Microsoft SQL Server Management Studio (SSMS).


  The database 'AdventureWorksLT2008R2' cannot be opened because it is version 661. This server supports version 655 and earlier. A downgrade path is not supported. Could not open new database 'AdventureWorksLT2008R2'. CREATE DATABASE is aborted. )Microsoft SQL Server, Error: 948)


So, I was wondering if it is possible to do something on the .mdf file so that the .mdf file will be downgrade to version 655 or earlier.

There is a similar question(s) such as this - Attaching database to the SQL server

The correct answer mention about getting to know more about the version and one suggest that latest Service Pack must be installed.

I have checked the version and notice that the latest Service Pack have been installed.

So, I was thinking of downgrade the mdf file but how do I downgrade it?
Simple answer: you cannot do that. 

There's no tool, no undocumented way, no hack, no workaround to achieve this. SQL Server database files just aren't "backwards" compatible - you can easily go from 2005 to 2008, or from 2008 to 2012 - but you cannot go backwards. 

You'll need to find another way to do this, e.g. by scripting out database structure and/or data into .sql files and running those on the old system.