This access denied error could have a few different causes. Basically, you don’t have the required access to the .MDF or .LDF files. This can happen if you get the file from someone else. When they detach the database file, the file permissions are changed to give only that user full control. Also, even if you see that the file has full control for the Administrators group, it may not be enough. Remember in Windows 7/Vista, those permissions are often only realized when you’re running an application as an Administrator.
So here are several choices to fix it:
- The easiest solution is to close SSMS and then run it as an Administrator. Perform the attach as an Administrator, and it’s likely going to work.
- Another solution is to explicitly grant full control to the .MDF and .LDF files to your user account. This can be done by right-clicking the files, selecting Properties, and modifying the Security tab.
- A final solution is to copy the files to the default directory for your other database files. To find out what that is, you can use the sp_helpfile procedure in SSMS. On my machine it is: C:\Program Files\Microsoft SQL Server\MSSQL10_50.SQLEXPRESS\MSSQL\DATA. By copying the files to this directory, they automatically get permissions applied that will allow the attach to succeed.
