The type or namespace name '

原文地址：http://stackoverflow.com/questions/35802657/unity-5-3-3-ui-does-not-exist-in-namespace

问题：Thetype or namespace name'UI'does not existinthe namespace'UnityEngine'(are you missing an assembly reference?)

解决方案：这个问题，是由于你的上次发布版本的时候用的webPlayer方式发布的原因导致的。

This happens when your last build target was "Web Player".

1   Open: File->Build Settings...

2  Choose PC, Mac & Linux Standalone

3  Build your game - during this step the VS solution settings will be fixed