The only one that I think has the “total trash effect” is the aswRvrt.sys boot hang issue.
You can search on this and there are a tons of threads.
What is bothersome is not only Normal mode but also Safe mode hangs.
A lot of help from Essexboy on FRST to remove Avast…some successful some not.
It is unclear if this aswRvrt.sys driver is the issue or what I understand is the mup.sys past it.
It is also hard to tell with all the different system configs if there are file system issues already on those systems.
What makes it more suspicious is many of these come up after a Windows Update and subsequent reboot.
Essexboy says the Avast Team is looking into this and trying to re-produce.
Since good portion of folks have to re-install there O/S then perhaps the recommendation is for people to first make sure you have a offline “image” of your HDD before upgrade…because you may not be able to use a system-restore or even a manual file system recover.
Also, as many have posted on threads…preferable to do a clean uninstall/install of Avast as opposed to GUI.
Lastly, perhaps a check of your system to make sure any old/previous A/V remnants have been uninstalled/cleaned.
Thus, perhaps the discussions/recommendations should not be “if” you upgrade but steps/preps when you do.