DCS Management Server upgrade from version 6.9.3 to 6.10 fails with "Failed to run SQL statement" error:

Error in MSI installation log located in user's profile Temp folder:
Failed SQL Statement:
'
USE [master];
DECLARE @SQL varchar(500);
SET @SQL = 'sp_addsrvrolemember N''' + 'sa' + ''', processadmin';
EXEC (@SQL);
'
DB Installer failed!
Exception thrown: java.lang.Exception: Failed to run SQL statement.
.......
Caused by: java.sql.SQLException: Failed to run SQL statement.
at com.symantec.dcs.server.install.sql.DbInstaller.executeSql(DbInstaller.java:1208)
at com.symantec.dcs.server.install.sql.DbInstaller.runSqlStatements(DbInstaller.java:1170)
... 8 more
Caused by: com.microsoft.sqlserver.jdbc.SQLServerException: Cannot use the special principal 'sa'.
at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDatabaseError(SQLServerException.java:261)
at com.microsoft.sqlserver.jdbc.SQLServerStatement.getNextResult(SQLServerStatement.java:1752)
Error with installation. Error code: 1
java.lang.Exception: Failed to run SQL statement.
MSI (s) (34!80) [02:00:39:476]: Product: Symantec Data Center Security Management Server -- Error with installation. Error code: 1
java.lang.Exception: Failed to run SQL statement.