SQLEXPRESS Backup File Losing NETWORK SERVICE User When Copied

I'm using the methods of the Microsoft.SqlServer.Management.Smo namespace within a .NET application to create a backup file from a SQLEXPRESS database. I can then restore the database from that backup device using methods in the same namespace. Here is a snippet from the restore code:


srv = New Server("MYPCSQLEXPRESS")

db = srv.Databases("washmaster")

Dim bdi As New BackupDeviceItem(BackupFileName, DeviceType.File)

Dim recoverymod As RecoveryModel

recoverymod = db.DatabaseOptions.RecoveryModel

rs.NoRecovery = False

rs.Devices.Add(bdi)

rs.Database = "washmaster"

rs.ReplaceDatabase = True

srv.KillAllProcesses("washmaster")

rs.SqlRestore(srv)


This works great as long as I used one of the backup files that I created directly on the disk. However, my application has a utility that allows the user to copy the backup files onto another drive, such as a CD or a thumb drive and when I try to restore from the copy of the backup, I get the following exception:

....Cannot open backup device..[filename]...Operating system error 5(Access is denied.)

The reason I get this error is that the "NETWORK SERVICE" account was removed from the file permissions when the file was copied.

How can I copy a backup to another drive and preserve the "NETWORK SERVICE" account? If I can't do that, is it wise to try to add the account back to the file before using it to restore or is there a better way?

Thanks,
SJonesy