I am having the same issue with disk and memory usage, I too have a Lenovo, mine is an IdeaPad and out of the box it had this issue, I uninstalled skype don't use it ever, none of these fixes posted have solved the issue. I let the system run idle for hours and check task manager and still at 100%. I go through the event logs and can not identify anything but I am not sure I would.
I have another Lenovo system that is maybe two years old and the same issue. Also when the disk usage is lower the memory usage is high over 50% typically 62% to 80%.. Both system are running 62% older one and 76% newer Lenovo. who knows.
I did notice on my phone that Onedrive uses a tonne of data in the background daily 5gb or more.
Host processing for sync..
system 77.5mb
service host unistack services group (4)
are top of the list when disk is 100%
memory has been at 62% for a long time top of the list
memory compression 543.4 mb
mcafee scanner services 105.5 mb
I do find it interesting that this usage is widely known and no concrete solution and this has to be taking a toll on out systems as continuous disk usage will cause premature disk failure. so a lack of an adequate resolution is a serious flaw on the part of the manufacturer as well as the operating system manufacturer as it is obviously one of their issues and it is causing financial harm as it is causing unusual wear and tear on the hard drive. I would say document all the fixes and solutions that you have done and been provided with so that when you have to purchase a replacement you know were to turn. Toshiba wasn't to happy when they had to replace my high end laptop and I dont think anyone is going to be to happy when this top of the line Lenovo needs replaced. Also make certain you have all the benchmark tests that have been done to show what normal usage should be.