laterv

Issue got solved by Windows update KB4522355: "Addresses an issue with high CPU usage in Desktop Window Manager (dwm.exe) when you disconnect from a Remote Desktop Protocol (RDP) session." https://support.microsoft.com/de-de/help/4522355/windows-10-update-kb4522355

Maybe the wall of links given in my first post might be a bit long winded. I'll try to sum up the info: Windows 10 1903 introduces a new display driver for remote desktop sessions (WDDM based Indirect Display Driver - IDD). As soon as a rdp session gets disconnected (i.e. the user is still logged in, but the rdp session is disconnected) the new driver causes the Desktop Window Manager (dwm.exe) to max out one cpu core. Until Microsoft comes up with a proper fix/update, the following workarounds are known so far: - Revert back to Windows 10 1809 - Switch off the new driver by disabling the following Group Policy: "Use WDDM graphics display driver for Remote Desktop Connections" in "Computer Configuration\Policies\Windows Settings\Administrative Templates\Windows Components\Remote Desktop Services\Remote Desktop Session Host\Remote Session Environment\" This Group Policy was introduced in Windows 10 1903. Configure it either locally via Group Policy Editor gpedit.msc or as a domain wide group policy object in Active Directory. The new Indirect Display Driver is related to another RDP issue in Windows 10 1903 as well: RDP showing a black screen when trying to establish a session. Because I don't wanna hijack this thread with possibly unrelated workarounds, I'm looking forward to feedback from affected users, first of all the OP.

Maybe some other Unraid users might appreciate the given background info. Yes, I've found this thread via Google and took the time to register as a new user in order to help you guys. I've only worked with XenServer, Freenas/bhyve, VMware and Hyper-V so far. No experience with Unraid yet. The issue discovered by the OP is not related to Unraid, Hyper-V or any other hypervisor. It's just another bug in Windows 10 1903. So sorry for answering the OPs question. Goodbye.

The issue the OP has observed is neither related to Unraid nor Hyper-V. It is just a bug in Windows 10 1903. I've been in contact to the rds dev team at Microsoft. The issue is under investigation. As of now, either stay at Windows 10 1809 or wait for a fix/update to resolve the issue in Windows 10 1903. Please have a look at the given background info instead of ranting at a newbie.

Having the same issue. Upgraded some Windows 10 1809 VMs on a Hyper-V host (Server 2016) to Windows 10 1903 yesterday. When disconnecting an RDP session (no logout, just disconnect), the dwm.exe of the RDP host surges cpu usage until the RDP session gets connected again. Upgrading Graphics drivers (Intel HD Graphics P630) didn't help. There are quite a few other reports on the same issue: english: https://answers.microsoft.com/en-us/windows/forum/all/dwmexe-high-cpu-one-core-on-target-system-after/dbce0938-60c5-4051-81ef-468e51d743ab https://answers.microsoft.com/en-us/windows/forum/windows_10-performance/after-exiting-a-remote-desktop-session-cpu-load/e21e7da0-9a64-4a14-a671-b7cb1b61f66e?auth=1 german: https://www.mikrocontroller.net/topic/476003 https://www.heise.de/forum/heise-online/News-Kommentare/Juni-Sicherheitsupdates-sabotieren-Ereignisanzeige-in-allen-Windows-Versionen/OT-Sei-1903-20-CPU-Load-von-DWM-exe-nachdem-RDP-Session-beendet-wurde/posting-34690755/show/ italian: https://social.technet.microsoft.com/Forums/it-IT/fc9ffe13-47d3-47ac-a1fc-c247d8f4ca8f/utilizzo-cpu-elevata-quando-si-esce-da-rdp?forum=win10itprogeneralIT#61fb43a6-1726-4e35-9ea8-74bc268dbd79 I've tried to report the issue to ms rds dev team ([email protected]). Please reach out to Microsoft as well to report the issue, e.g. via feedback hub.