Windows 10 April 2018 Update may boot to a “Choose your keyboard layout” screen or to a blank screen with a Recycle Bin

Here's what I did to fix my husband's laptop:

There are two methods to fix this update problem that are recommended by Avast and Microsoft: https://answers.microsoft.com/en-us...a-choose/8ff0d933-8819-4945-9f0c-17ac854400e2. The first tells you to do a rollback, the second suggests an in-place upgrade. Both stink if you can't reach the command prompt, which I couldn't because I was only offered the suggestion of logging into my account which wouldn't accept the password, despite the fact that it was correct. 
Now the steps that I followed that ultimately end up working (yay!). I started using Microsoft's steps until they didn't work anymore.

From "them" - To restore your system, you will need:

• A blank USB drive with at least 8 GB of disk space
• Another working Windows PC that you can use briefly (for example, a 2nd computer in your home, a friend’s computer, or one at a library or print shop)

1. On a working PC, go to the Microsoft software download website.
2. Download the media creation tool and then run it. (be sure to format the USB drive first or this will fail, and be prepared for this to take awhile)
3. Select Create installation media for another PC.
4. Choose a language, edition, and architecture (64-bit or 32-bit). (if you have a newer laptop it's probably 64 bit)
5. Follow the steps to create installation media on your USB drive, and then select Finish.
6. Now from here on out this is what I did: Get your wrecked laptop to the Choose An Option screen then choose "Use a device"
7. On the next screen I chose EFI USB Device
8. It then got my USB blinking and popped up a window saying "It looks like you started an upgrade and booted from installation media. if you want to continue with the upgrade, remove the media from your PC and click Yes. if you want to perform a clean installation instead click NO."
9. I chose No and it got me to a Windows popup asking for language, time & currency, & keyboard method. I clicked Next and the next window showed "Install now." Repair your computer is an option at the bottom, but it just goes to those wonderful options that we've all been seeing that don't work so don't bother pressing that.
10. I pressed Install Now and it wanted to know where to install. I chose the first, highlighted, partition option.
11. At this point it started rolling. I may have had something asking if I wanted to overwrite or upgrade or something. There was an option to either upgrade or to do a custom installation. I THINK I did the custom installation. All files were saved to OneDrive in the first place, so we weren't worried about losing stuff.
12. Be ready with a new Windows password. We went to a functioning computer and did the "forgot password" link for Windows so that we would be confident that we were using the right password.
13. After installation Cortana appeared with her slew of questions and at this point you will need to log into Windows. This is where it pays to be ready with the password because we ran out to get a new one and then the computer went black aside from the pointer. I had to pull the power plug while holding the power button to totally shut down (just holding the button until shut down still produced the same black screen upon startup). After the "real" power down it returned back to Cortana when it restarted.

Updated (5/25/18):

In cooperation with Avast, Microsoft has identified an element of the Avast Behavior Shield that conflicts with the April 2018 Update, and that may result in this experience.  Avast has released an update to prevent this issue from occurring.  Once you’ve restored your system, make sure your Avast antivirus is up-to-date.

You can use one of the following methods to restore Windows.  If your system currently boots to the Choose your keyboard layout screen, please try Method 1 first.  Otherwise, skip to Method 2, which is a variation of a solution posted on the Avast forums. 

Method 1:  Use Command Prompt to repair Windows Rollback

1. At the “Choose your keyboard layout” screen, select a keyboard (such as US).
2. At the “Choose an option screen”, verify that the top left tile reads “Continue – Exit and continue to Windows Rollback”. If this is not the case, please do not proceed further and use Method 2 instead.  
3. Select Troubleshoot.
4. Select Command Prompt.
5. In the cmd.exe window, type bcdedit and press Enter.
6. There should be 4 entries displayed.  Ignore the first entry, called {bootmgr}.  The next entries should all have an attribute called “device” or “bootstatdevice”, which will have a value similar to partition=E:
7. In the cmd.exe window, switch to the drive letter you noted in the previous step.  In this example, you would type E: and press Enter.
8. Type the following command and then press Enter:

copy \Windows.old\Windows\System32\OOBE\SetupPlatform\SetupPlatform.exe \$WINDOWS.~BT\Sources

9.  When completed, you should see the output, “1 file(s) copied”.  If you see any other output, please do not proceed further and instead use Method 2

10.   In the cmd.exe window, type exit and press Enter.  This should return you to the Choose an option screen.

11.  Select Continue – Exit and continue to Windows Rollback. 

12.  Your device should restart and Windows Rollback should then successfully restore your system to the previous version of Windows.  Once you are successfully restored, Microsoft recommends that you do not attempt to manually install the April Update – please wait until Windows notifies you that the update is ready for your device.

Method 2:  Perform an in-place upgrade

To restore your system, you will need:

• A blank USB drive with at least 8 GB of disk space
• Another working Windows PC that you can use briefly (for example, a 2^nd computer in your home, a friend’s computer, or one at a library or print shop)

1. On a working PC, go to the Microsoft software download website.
2. Download the media creation tool and then run it.
3. Select Create installation media for another PC.
4. Choose a language, edition, and architecture (64-bit or 32-bit).
5. Follow the steps to create installation media on your USB drive, and then select Finish.
6. On the computer that is experiencing the problem, use the power button to restart until it boots to the blue recovery screens.  (You do not need to boot to the USB drive you just made.)
7. At the Choose your keyboard layout screen, choose your keyboard layout (e.g., US).
8. At the Choose an option screen, select Troubleshoot.
9. Select Command Prompt.
10. In the cmd.exe window, type C: and press Enter.  (If Windows is saved to a drive other than the C: drive, type the appropriate drive letter.)
11. Type the following command and press Enter.  This command renames the Windows.old folder to protect your personal files from being overwritten in certain scenarios.

Ren Windows.old Windows.old.bak

12.  In the cmd.exe window, type exit and press Enter.  This should return you to the Choose an option screen.

13.  Select Use another operating system.

14.  Select the second option, “Windows 10 on volume X”, where “X” will be a number.

15.  Wait for Windows to load the desktop.  (If necessary, enter your password to sign in.)  You may have to wait a long time for the desktop to appear while the “update” gets ready.

16.  Once the desktop attempts to load, close any error messages that appear (such as “C:\WINDOWS\system32\config\systemprofile\Desktop is unavailable”).

17.  Right-click any blank area on the taskbar, and then select Task Manager.

18.  If necessary, select More details, so that you can see the Menu bar.

19.  Select File, then Run new task.

20.  In the dialog box that appears, check the box for Create this task with administrator privileges.

21.  Select Browse…

22.  Insert the USB drive you used to create installation media on the working computer.  Navigate to your USB drive and select setup.exe.

23.  Run the setup.exe file and follow the steps to “upgrade” Windows.  Uncheck the boxes for “check for new updates” and “help make this version better”.  If you are asked what you want to keep, make sure you tell it to keep everything!

24.  Setup may take some time to run.  Once completed, your system should be restored and fully up-to-date.  You may need to sign in again to your Microsoft Account.

25.  If you lost any personal files during the upgrade process, you can retrieve your files from the Windows.old.bak folder you created in step 11.  Open File Explorer and navigate to C:\Windows.old.bak.  Select the Users folder, and then your user account name.  Open the folders that contain the files you want to retrieve and copy/paste the files into a desired location.