Hi Richard Cross,
If you are trying to attach an mdf file to SSMS while the website is still running you will not be able to do this. This is because the application pool identity in which your website is running is putting a lock on the mdf file since it is working with it. What you have to use is to stop the website, attach the mdf file and schange the connection string in ~/App_Data/Sitefinity/Configuration/DataConfig.config to use the database attached to your SQL server. Then you will be able to perform automatic backups.
All the best,
the Telerik team
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