DigitalMooney said,
How to fix 100% disk usage in Windows 10
This is caused by a common combination of Skype as well Google Chrome. Similar issue with other programs could also cause 100% disk usage. To fix this do the following:
<snip of a detailed solution>
I have had a similar problem of 100% disk usage in W10 for the last week (along with missing start menu, Cortana and other odd behaviors for more than three months after the update), but I use neither Skype nor Chrome. This morning when I logged on, there was a "disk repair" process going. The system logged off when complete, and when I signed on again all disk usage had dropped to 0% (or nearly so). ****?? Of course I still don't have the Start menu or Cortana, but I've learned how to get around with this crippled system. I've done NOTHING that I can attribute this change to [it appears there have been no mystery updates] -- I'm just holding my breath.
Richard