Database upgrade fails with creation or removal of constraints such as indexes (4314779)

Database upgrade fails with creation or removal of constraints such as indexes. Below are a few errors that may occur:

• The operation failed because an index or statistics with name "IX_tblTaskError_TaskId" already exists on table dbo.tblTaskError  (Microsoft SQL Server, Error: 1913)

• Column names in each table must be unique. Column name 'OldSlotCount' in table 'dbo.tblDiscoveryNode' is specified more than once.

• ERROR ExecuteSqlScriptTask.Execute: Exit (RunSQLScript threw an exception) : Microsoft.SqlServer.Management.Smo.FailedOperationException: ExecuteNonQuery failed for Database 'dbReporter'.  ---> Microsoft.SqlServer.Management.Common.ExecutionFailureException: An exception occurred while executing a Transact-SQL statement or batch. ---> System.Data.SqlClient.SqlException: 'FK_tblNTFSChangeData_ID_tblNTFSChangeHistory' is not a constraint.