I'm a fan of black themes, windows 10 doesnt really like this. Upon updating and rebooting I had a black screen with nowt but a cursor, this is a fix for that

First thing is just to check that explorer is actually broken and not just autostarting

1. Ctrl+Alt+Del
2. task Manager
3. File > run new task
4. type explorer.exe and hit enter

if that doesnt work open task manager back up and this time:

1. type Powershell and hit enter
2. run Set-ItemProperty -Path "HKCU:\Software\Microsoft\Windows\CurrentVersion\Themes" -Name LastHighContrastTheme "C:\WINDOWS\resources\Themes\aero.theme"
3. run Set-ItemProperty -Path "HKCU:\Software\Microsoft\Windows\CurrentVersion\Themes" -Name CurrentTheme "C:\WINDOWS\resources\Themes\aero.theme"
4. run remove-item $env:localappdata\Microsoft\Windows\Themes\RoamedThemeFiles\* -force
5. run remove-item C:\windows\resources\themes\*.theme -exclude aero.theme -force -whatif
6. run shutdown.exe -r -t 00