HDD being thrashed for about 10 minutes on EVERY restart

In the last few weeks, my HDD is being thrashed for about 10 minutes after every reboot of Windows 10.
I am almost unable to use normal apps/games till this thrashing stops.
Looking at Task Manager, it seems like AntiMalWare (Defender) seems to be at the top of the list most of the time with 'system' up there as well.
Didn't used to happen. Creator update?
Any help appreciated.

dalchina said:

Hi, there's probably a good answer, but when I initially installed Win10 a couple of years back, my first reaction when I saw Defender doing that (which it shouldn't and I guess doesn't for most people) was to install Avast. Sorry I can't give you a direct answer- perhaps someone who uses Defender can.
As to whether that's anything to do with the Creator's upgrade, you will know if you have that as you will have seen the lengthy upgrade process proceed.

Thanks. I might give Avast a go.
I have the Creator update, what I meant was could it be that causing the issue as it's only been happening on the last few weeks. Might be coincidence.