I had the same problem just yesterday. I did the following - don't know which fixed it.
1. Disable Windows Search
- from an elevated command prompt, type net.exe stop "Windows search"
. You'll have to go into the services applet to disable it permanently, but that should stop it for long enough for you to see if it is just that. It wasn't for me, but after some thought, I went ahead and disabled it anyway because of my third piece of advice below.
2. Disable Superfetch
. I remembered something about this from when w10 first came out. Similarly to the above, the command is net.exe stop superfetch
. Same applies as above if you want to make this permanent.
3. After I did the above, I didn't notice a difference. So I ran chkdsk, and disabled both of the above permanently before I rebooted for the chkdsk. command, just for completeness: chkdsk.exe /r
After that ran, the usage stopped after reboot. Again, not sure which step fixed it... I guess I could have done it more scientifically, but I wasn't doing it for science.