Configure File System Permissions for Database Engine Access
This topic describes how to grant the SQL Server Database Engine, file system access to the location where database files are stored. The Database Engine service must have permission of the Windows file system to access the file folder where database files are stored. Permission to the default location is configured during setup. If you place your database files in a different location, you might need to follow these steps to grant the Database Engine the full control permission to that location.
Beginning with SQL Server 2012 (11.x) permissions are assigned to the per-service SID for each of its services. This system helps provide service isolation and defense in depth. The per-service SID is derived from the service name and is unique to each service. The topic Configure Windows Service Accounts and Permissions describes the per-service SID and provides the names in the section Windows Privileges and Rights. It is the per-service SID that must be assigned the access permission on the file location.
To Grant File System Permission to the Per-service SID
Using Windows Explorer, navigate to the file system location where the database files are stored. Right-click the file system folder, and then click Properties.
On the Security tab, click Edit, and then Add.
In the Select Users, Computer, Service Account, or Groups dialog box, click Locations, at the top of the location list, select your computer name, and then click OK.
In the Enter the object names to select box, type the name of the per-service SID name listed in the Books Online topic Configure Windows Service Accounts and Permissions. (For the Database Engine per service SID name, use NT SERVICE\MSSQLSERVER for a default instance, or NT SERVICE\MSSQL$InstanceName for a named instance.)
Click Check Names to validate the entry. (If the validation fails, it might advise you that the name was not found. When you click OK, a Multiple Names Found dialog box appears. Now select the per-service SID name, either MSSQLSERVER or NT SERVICE\MSSQL$InstanceName, and then click OK. Click OK again to return to the Permissions dialog box.)
In the Group or user names box, select the per-service SID name, and then in the Permissions for <name> box, select the Allow check box for Full control.
Click Apply, and then click OK twice to exit.