Windows 10: Reconnecting to RDP session hangs

Publication date: 2019-08-21

Issue: Reconnecting to RDP session hangs on Windows 10 until server restart

Solution: Don't use WDDM graphics display driver

Add the following line to Windows registry and reboot:

reg add "HKLM\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services" /v fEnableWddmDriver /t reg_dword /d 0 /f

This forces RDP to use the old (and now deprecated) XDDM drivers.

This is possibly equivalent to setting the following group policy to disabled:

Local Computer Policy
 Computer Configuration
  Administrative Templates
   Windows Components
    Remote Desktop Service
     Remote Desktop Session Host
      Remote Session Environment
       Use WDDM graphics display driver for Remote Desktop Connections

Hint towards the solution

"It seems last updates can use wddm drivers causing dwm.exe cpu high or hang system , when two remote users close session without log out and if one user close session without log out, no hang, but if reconnect to existing session , system hang on VM. It works for me now, disabling that new setting using this GPO https://answers.microsoft.com/en-us/windows/forum/all/dwmexe-high-cpu-one-core-on-target-system-after/dbce0938-60c5-4051-81ef-468e51d743ab" (Source: https://github.com/stascorp/rdpwrap/issues/858 https://github.com/stascorp/rdpwrap/issues/858)