SQL Server Error 4616 - You cannot perform this operation for the restore database
You may be aware default 4 SQL Server system databases master, model, msdb & tempdb are created automatically when the SQL Server is installed. Those databases files can be located under default directory assuming C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\Data and when you look into this directory additional data file - Mssqlsystemresource.mdf. You will be surprised to see this particular data file's database cannot be found in Enterprise Manager or SQL Server Management Studio.
This file is for a resource database that has been added to 2005 version and if you try to attach this .MDF file to your installation it will error to: You cannot perform this operation for the restore database (Microsoft SQL Server, Error 4616). The error is by default as this database is a read-only system database that cannot be accessed and it will be used only during the upgrade process. Also when you want the upgrade procedure to newer version of SQL Server faster then you need to copy this file to the local server instance that contains the system objects.
Never attempt to force-open this particular .mdf file, you will be risking the replication process too.