Hi all.
I had this problem too, on several of my company PCs.
I noticed Windows 10 keep using 100% of disk when Windows Update service is running.
Despite the fact "active hours" of all our PCs configuration is set to 8am to 20pm, Windows Update downloads and installs updates in background (maybe it's normal, I don't know -- but it's exaclty the reason that made our disks get stuck...).
Moreover, in august Microsoft released a cumulative update (2018-08) that blocked on 100% disk usage all PCs.
It installs it in background, BUT it needs a MANUAL reboot to complete the installation, and no notifications are showed since our set up of "active hours".
So, the only solution for me was:
- keep waiting Windows Update dowloads and installs everything it needs OR go to settings and force Windows Update to search for updates,
- reboot the PC manually.
These steps magically restore disk usage to about 1- 2%...
Another known problem is that sometimes Windows 10 does not retrieve correct drivers, when the OS installation is made from a previous disk image (with backup/restore programs...)
Hope this helps.