Windows 10 Reset local account

Load the recovery and troubleshooting environment, e.g. by clicking on ”Repair your computer” during Windows Setup if you boot from Windows installation media.
Select Troubleshoot > Command Prompt.
Switch to the drive letter that Windows is installed on and there in the system32 directory, e.g. cd c:\windows\system32
Type rename utilman.exe utilman.bak.
Type copy cmd.exe utilman.exe.
Restart the computer and boot from the Window installation this time.
If you run Windows 10 version 1803 or earlier, click on the Ease of Access button to open a command prompt window.
If you run Windows 10 version 1809 or later, do the following first:
1. Hold Shift-key on the keyboard and click on the Power button to select Restart.
2. After the Restart, hold down the Shift-key again and select Restart from the Power menu again to boot into startup repair.
3. Select Troubleshoot > Advanced Options > Startup Settings > Restart
4. When the Startup Settings screen appears after the Restart, select 8) Disable early launch anti-malware protection.
Click on the Ease of Access button on the next start on the login screen to open the command prompt window.
Type net user to display the names of all user accounts.
Use the command net user [username] [password] to change the password of the account, e.g. net user martin qwerty123456 to change the password of the user martin to qwerty123456.