Timestamps (*) and assets (*) maps out of sync.
Asset 'C:/Program Files (x86)/Unity/Editor/Data/UnityExtensions/Unity/GUISystem/4.6.0/UnityEngine.UI.dll' is in timestamps but is not known in guidmapper...
Asset 'C:/Program Files (x86)/Unity/Editor/Data/UnityExtensions/Unity/GUISystem/4.6.0/Editor/UnityEngine.UI.dll' is in timestamps but is not known in guidmapper...
1.关闭UNITY
2.找到C:/Program Files (x86)/Unity/Editor/Data/UnityExtensions/Unity/GUISystem文件夹并拖出到桌面
3.启动UNITY无法运行，并退出
4.强GUISystem文件夹拖回C:/Program Files (x86)/Unity/Editor/Data/UnityExtensions/Unity/
5.打开UNITY错误消除