On February 18, 2013 Microsoft released SQL Server 2012 RTM Cumulative Update 6, which is Build 11.0.2401. This CU has 22 fixes listed in the public fix list, which is quite a bit fewer hotfixes than in the first five cumulative updates for the RTM branch of SQL Server 2012. I take this as a sign that the SQL Server 2012 code base is becoming more stable, which is always a good thing.

This cumulative update is only for the RTM branch of SQL Server 2012. It will not install or work with SQL Server 2012 Service Pack 1 (or any other version or service pack level). The fixes in this cumulative update are not yet available in a cumulative update for SQL Server 2012 Service Pack 1. You will have to wait about a month for SQL Server 2012 Service Pack 1 CU3 to be released.

Microsoft has the RTM and Service Pack 1 branches of SQL Server 2012 out of synch as far as cumulative update releases are concerned, with the RTM branch being “ahead” of the Service Pack 1 branch. That means that if you have “done the right thing” by moving to SQL Server 2012 Service Pack 1, you have to wait about a month to reach parity with the RTM branch. Microsoft did not have this issue for SQL Server 2005, 2008, or 2008 R2 (except for a slight delay right after a new service pack was released), and they are not currently planning on fixing this issue (as far as I have been able to determine).