Keep your system up to date with the most recent cumulative update package for SQL Server 2005 SP4. SQL Server 2005 SP4 Cumulative Update 1 contains fixed released in SQL Server 2005 SP3 CU 12. For customers upgrading to Service Pack 4 from SQL Server 2005 SP3 CU12 (Build 9.00.4311) should consider applying SQL Server 2005 SP4 CU 1 to ensure fixes presented in SQL Server 2005 SP3 CU 12 are available on their systems post upgrade to Service Pack 4.
CU#1 KB Article: http://support.microsoft.com/kb/2464079
Understanding Incremental Servicing Model for SQL Server
SQL Server Support Information: http://support.microsoft.com/ph/2855
SQL Server Sustained Engineering
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