Solved: Black Screen (No Task Bar, No Desktop).

Symptom:
After upgrading to Windows 10 1607 I got a black screen with no desktop and no task bar after login.
All programs work, if you start them from the task manager with “Run new task”.
Restart of the explorer does not work. It only opens “Quick access”.

Even “safe mode” shows the same symptom.

Cause:
A long time ago I made some experiments with remote apps.
So rdpinit.exe was called after/with login. This was no problem with
1511 or Win10 1507, but after upgrading to 1607 I got this error.

Resolution:
Change
              HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Userinit
from
              "c:\Windows\system32\userinit.exe, rdpinit.exe,"
to
              "c:\Windows\system32\userinit.exe,"

Notes:
x64-Users may have to check
              HKLM\SOFTWARE\WoW6432Node\Microsoft\Windows NT\CurrentVersion\Winlogon\Userinit
also.