While I can understand your points about disk defragging in NU16, if you have a license for NU15 there is nothing stopping you uninstalling NU16 and re-installing NU15. Of course NU15 is not compatible with Windows 8/8.1.
While I can understand your points about disk defragging in NU16, if you have a license for NU15 there is nothing stopping you uninstalling NU16 and re-installing NU15. Of course NU15 is not compatible with Windows 8/8.1.