Hi!
I have the same problem, i could not install KB4493132 either.
My AVAST version is 19.4.2374 (build 19.4.4318.439)
My Windows version is Windows 7 Home Premium 32bit HU.
The upgrade stops at 67, or 69%, if i try to reboot the computer, stops at 36%.
Only rollback helps on my computer, it never reach the login screen (tried 3 times, for 3 hours...).
I hope this helps to find the problem.
Peter