after avast updated, can't playing overwatch

when I was playing overwatch, suddenly my avast updating. so i reboot my computer, and rejoin the overwatch.
But overwatch just crash, frame drop, even reboot my computer
when i shutdown the avast, overwatch working great no problem!
why is this happening??
korea overwatch reddit people soooooo mad for this problem!!! >:(

https://forum.avast.com/index.php?topic=201784.0