Grey screen with one of two users after Windows 10 upgrade from Windows 7

Hi Bruce,

Thank you for posting your query in Microsoft Community.

I can understand, how frustrating it can be, when things don’t work as expected.

We apologize for the inconvenience caused.

I'd be glad to help you.

Let’s try to login via your child’s user account and try to follow these steps, mentioned below, to resolve the issue:

1. Use the power button on the sign-in screen to Shift+Restart. This will take you to the recovery boot menu.
2. Click Troubleshoot, Advanced options, Startup settings. When given the choice of startup options, try booting the PC in Safe Mode with Command Prompt. If you can’t get there, skip to the next major step.
   1. If you can get to a CMD window, enable the built-in administrator account:
      net user administrator /active:yes
      Note: If this fails, check to see if there is a different language in use and use the correct “Administrator” name from the list here.
   2. Then restart and sign-in as the Administrator account.
   3. Once in the Administrator account, open Regedit and go to the following key:
      HKEY_USERS\.DEFAULT\Software\Microsoft\IdentityCRL\StoredIdentities
   4. Save a backup of the key: Export the StoredIdentities key to a .REG file on the desktop.
   5. Then continue with step 4 below.
3. Use boot media to access the recovery command prompt.
   1. Start Regedit.
   2. Select the HKEY_USERS key.
   3. Click File, Load Hive. and go up in the file system to This PC. Then browse to this file and then click Open:
      C:\Windows\System32\config\DEFAULT
   4. When prompted, name it “def”
   5. Select this key:
      HKEY_USERS\def\Software\Microsoft\IdentityCRL\StoredIdentities
   6. Save a backup of the key: Export the StoredIdentities key to a .REG file on the C:\ drive.
4. Find the subkey under StoredIdentities that matches the name of the Microsoft Account.
5. Delete the key.
6. If you loaded the offline registry hive, go back up in the tree on the left and select “def”. Then click File, Unload hive. This option will only be available if “def” is selected.
7. Restart the PC and test sign-in.
8. Once done, you may need to verify the account in Settings, Accounts in order for it to be fully usable in Windows again.

If you used the built-in Administrator account to resolve the issue, please return it to the default disabled state to help keep the customer’s PC secure. To do that, refer this command after trying the above steps: net user administrator /active:yes

Registry disclaimer

Note: This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

322756 (http://support.microsoft.com/kb/322756/ )

How to back up and restore the registry in Windows

Hope this information helps you. Kindly post back with the updated issue for further assistance.
 
 Thank you.