it's november 2018 and this is still happening, ESPECIALLY on win10 (any version/build). on EVERY reboot, the avast service (32 bits) completely trahses the HD for 5 to 10 minutes. Uninstall avast, problem solved, computer is A LOT MORE responsive on startup and no 100% constant disk usage. I've seen this on dozens of PCs. it's not one particular case. No other AVs running, not even defender crap.