I’m using Windows 10 (64) and have no problems with Unreal Engine (4.9.2 and 4.10.0) so far.
One thing is worth mentioning though. I’m using the engine for ~9 hours each day, sometimes without restarting it. After the so continuous usage it starts lagging, but I believe it’s due to my very slow PC (Intel i3-4000M 2.4 GHz 4GB RAM).