SqlExpress mdf DB incompatibility

I used the ASP.NET (.NET4) default ASPNETDB.mdf database that gets created when using membership, in one of my sites. I then copied the site to the web server. Now it has been running for a while so there is content and comments. But I now need to make changes to the code that will also require extra fields in the db, so I copied the .mdf from the server to my local machine to edit and add the fields(so I didnt lose content etc). But when I run the project after replacing the mdf i get the following error:

"The database ".....APP_DATA\ASPNETDB.MDF" cannot be opened because it is version 661. This server supports version 655 and earlier. A downgrade path is not supported. Cannot open user default database. Login failed. Login failed for user 'Me-PC\Me'.

This confuses me, as it is the exact mdf file that my home VS generated. The server is running the开发者_如何学JAVA same .NET as I am too, so I dont see why it would have changed anything.

Thanks!

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Ok, so it turns out the server was running a different version of MSSql Server 2008 R2 (yeah?) which meant that the db file was getting upgraded, so when it came back to my lowly system it failed. Had to uninstall and reinstall both VS 2008 and SQL Server 2008