This article was previously published under Q322988
When you try to add the Local System Account to Microsoft SQL Server on a computer that is running Microsoft Windows NT 4.0 (for example, sp_grantlogin 'NT AUTHORITY\SYSTEM'), the attempt fails and you receive the following error message:
Server: Msg 15401, Level 11, State 1, Procedure sp_grantlogin, Line 41Windows NT user or group 'NT AUTHORITY\SYSTEM' not found. Check the nameagain.
NOTE: By default, the Local System Account is a member of the local Administrators group and is therefore a member of the sysadmin group in SQL Server.
The only way to grant "Local System Account" (NT AUTHORITY\SYSTEM) access to Microsoft SQL Server is to use the post-Microsoft Windows NT 4.0 Service Pack 6a (SP6a) Security Rollup package.
For additional information about this fix, click the article number below to view the article in the Microsoft Knowledge Base:
299444 Post-Windows NT 4.0 Service Pack 6a Security Rollup Package (SRP)
To work around this problem, upgrade the operating system from Microsoft Windows NT 4.0 to a more recent platform. For example, upgrade the operating system to Microsoft Windows 2000 or to Microsoft Windows XP.
For additional information, click the article number below to view the article in the Microsoft Knowledge Base:
216808 PRB: Use BUILTIN\Group to Grant Access to Predefined Windows NT Groups
263712 INF: How to Prevent Windows NT Administrators from Administering a Clustered SQL Server
NOTE: After you perform changes on Microsoft Data Access Components (MDAC) components, you must reapply the post-Windows NT 4.0 SP6a Security Rollup package.