I don't have the normal Win 10 Tech Preview install anymore in Hyper-V but I do have
Windows Server Technical Preview Build 9841 running in Hyper-V and enhanced session mode seems to run fine. That would be the equivalent of the initial version of Windows 10 Tech Preview, just the server version.
I configured my settings according to this page here http://www.virtualizationadmin.com/...nced-session-mode-windows-server-2012-r2.html
Both in Hyper-V manager and in the VM settings and it seems fine.