Well, we can now report some good news for those that use Avast and want to get the Windows 10 April 2018 Update, or those that previously installed the update (before Microsoft blocked it) and now find themselves with an unusable computer.
Avast and Microsoft determined that the Avast Behavior Shield is what's causing the incompatibility with the April 2018 Update. "Luckily, we have found a way to prevent the problem and are now automatically pushing a VPS update to all customers which makes sure that the problem doesn't happen," wrote Avast global moderator Vlk. "The VPS number is 180524-08; all users running this version (or later) should be 100% safe."
For people that have not yet upgraded to the Windows 10 April 2018 Update, the above software patch will allow you to upgrade without issue.
For those that have a non-functional system due to uses the older, incompatible version of Avast antivirus software, you'll need grab an 8GB (or larger) USB thumb drive, find a Windows computer that is actually working and follow these instructions:
- Turn on the problem computer.
- At the blue screen, choose your keyboard layout’s language. (e.g. "US")
- Choose "Use another operating system".
- Choose the second option, "Windows 10 on volume X" (X stands for a number)
- Wait for the computer to boot to the desktop (if necessary, enter your password to login). You may have to wait a long time for the desktop to appear, while the "update" gets ready.
- Once the desktop attempts to load, close any error messages that appear.
- On a functioning Windows PC, go to www.microsoft.com/en-us/software-download/windows10.
- In the "Create Windows 10 installation media" section, click "Download tool now".
- Run the tool you downloaded, and follow the simple steps to create a Windows 10 installation USB stick. This will erase any existing contents of your USB drive. The only option you should check is to make sure it is a 64-bit or 32-bit version. Your computer is MOST LIKELY 64-bit if it's reasonably new.
- On the problem computer, right-click any blank area on the taskbar, then click "Task Manager".
- Click "More details" so that you can see the menu bar.
- Click "File".
- Click "Run new task".
- In the dialog box that appears, check the box "Create this task with administrative privileges"/
- Click "Browse…"
- Navigate to your USB drive and select "setup.exe".
- Run the file and follow the steps to "upgrade" Windows. Uncheck the boxes for "check for new updates" and to "help make this version better". If you are asked what you want to keep, make sure you tell it to keep everything!
- Let the process run, which may take some time. Once completed, the computer should be back to normal, and fully up-to-date. You may need to re-login to your Microsoft Account.
The above steps should [hopefully] get your borked system back up and running with no loss of data. We should mention that Avast is seemingly deflecting some of the blame away from itself with this incompatibility, as it says that it only affects a "small subset" of users and that is an issue that is also affecting other software -- not that this is any consolation to those that have been sidelined as a result.