The Operating System Column in Device data is empty for all the devices. All the OS are listed there in Operating System Master data however when we are checking the Device data, the OS filed is empty.
dTb.[OS] as Operating_system. Is the Query which is being used.
In newer systems the table operating systems is split of the devices table, so you need to import operating systems into the tables operating system and reference it in the device import by using
dTb.[os] AS import_operating_system_id.