As the title suggests, after updating Windows 10 computers to 1803, users have reported slow RemoteApp sessions.
You can try disabling Remote FX, but user reports suggest this causes further issues.
The easiest fix is to copy mstsc.exe and mstscax.dll from a 1709 build and replace the files on 1803. We have confirmed this works.
This morning we awoke to screams from users not being able to login to our remote desktop servers.
KB4103727 has been released which switches a flag to protect against the CredSSP attack.
The quickest way to fix this to get your users working is to patch your domain controller with the May updates and use group policy to push out a change
You can manually add this to the registry for desktop clients
or via command line
reg add "HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\CredSSP\Parameters" /f /v AllowEncryptionOracle /t REG_DWORD /d 2
To fix this problem, the May updates need to be installed on all servers and workstations.