I am facing an issue at this issue in my environment. Copy / paste works when I login first time using mstsc. Once I disconnect my session, and connect again after time, Copy/paste stops working. I have to kill rdpclip.exe and start again to get copy/paste working again.
This happens for all the users on the server.
I have run sfc /scannow, and utility has returned " No integrity violations found ".
Host machine : Windows Server 2012
Target: Windows 10