PHDM 15 - Back up operating system / Back up volumes options, what's the difference?

Hello,

what's the actual practical difference between Back up volumes and Back up operating system backup options?

The manuals says - Select Back up operating system to create a sector-level virtual container of the entire operating system. If you want to back up individual volumes, please select the Back up volumes option.

I sequentially backed up and restored my system on C: (Win 7) using both of the options, with the same great result. The archive sizes were almost the same.

So what's the practical difference between these 2 modes, when it comes to system backup? I'm used to HDM 14, which didn't have this dilemma.

Thanks in advance!

i see option for "WHOLE COMPUTER", or "DISK/PARTITION"; i dont see option for "OPERATING SYSTEM'. could you post a screen shot where that option is?