First of all "Northwind" and "AdventureWorksDW2008" databases attached without problem, but "AdventureWorks2008" fails with the following error. // Msg 5120, Level 16, State 105, Line 1 Unable to open the physical file "C:\Program Files\Microsoft SQL Server\MSSQL10.MSSQLSERVER\MSSQL\DATA\Documents". Operating system error 2: "2(The system cannot find the file specified.)". Msg 5105, Level 16, State 14, Line 1 A file activation error occurred. The physical file name 'C:\Program Files\Microsoft SQL Server\MSSQL10.MSSQLSERVER\MSSQL\DATA\Documents' may be incorrect. Diagnose and correct additional errors, and retry the operation. Msg 1813, Level 16, State 2, Line 1 Could not open new database 'AdventureWorks2008'. CREATE DATABASE is aborted. //

PS: I did not use the default database instance "MSSQLSERVER" during install, so Where is it finding this path "C:...\MSSQL10.MSSQLSERVER...\Documents"?