Remote Desktop event ID 20499. No noticeable issues
Solution 1:
This will solve your problem:
In Registry Editor, locate and then click one of the following registry subkeys:
HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows NT\Terminal Services
Add DWORD fQueryUserConfigFromLocalMachine with value 1
restart
Reference https://support.microsoft.com/nl-nl/help/4021856/sbsl-issue-when-you-create-an-rdp-connection-to-windows-server
Solution 2:
Apparently this can be triggered by using mRemote / Remote Desktop Connection Manager (RCDMan 2.2) or similar software.
The fix is to set TaskOffload = Disabled
using Set-NetOffloadGlobalSetting
Source: http://www.itnotes.eu/?p=1193