Both Windows defender and Avast is running

I just updated Avast, and suddenly both Windows defender(Antimalware Service Executable is the name of the process), and Avast is running at the same time. Now, I am no genius when it comes to computers, but shouldn´t

it only be Avast that is running?

Can I or should I do something about it?

c¨,)

Just disable Windows Defender.