SQL Server 2008 R2 cumulative update was giving an error stating SQL Server setup failure.
SQL Server Setup has encountered the following error:
A failure was detected for a previous installation, patch or repair for instance “MSSQLSERVER” during the configurtion for features………. Error code 0x84B20001
Found it on Microsoft forums and other posts to look for these registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSSQL10_50.MSSQLSERVER\ConfigurationState
All REG_DWORD values were set to 3 and changed them to 1.
Wow, this time the setup validation succeeded and the SQL server 2008 R2 update operation was completed successfully.