Matt Slocum ran into a production issue with a cluster name that changed:
Next is just a simple matter of updating the registry value. I launched Registry Editor (RegEdit.exe) and navigated to HKLM > Software > Microsoft > Microsoft SQL Server > MSSQL12.MSSQLSERVER > Cluster
Note: MSSQL12.MSSQLSERVER will vary based on SQL version (SQL 2012 is “MSSQL11”) and instance name (“MSSQLSERVER” is the default instance and named instances are the actual instance name instead of “MSSQLSERVER”).Within the Cluster key I updated the value of ClusterName to match what was specified in Failover Cluster Manager
This is a good diagnosis and resolution of an issue.