unity引用vuforia-unity-6-2-10出错

error CS1704: An assembly with the same name Vuforia.UnityExtensions.Editor' has already been imported. Consider removing one of the references or sign the assembly
F:/unity-2018.1/Unity/Editor/Data/PlaybackEngines/VuforiaSupport/Managed/Editor/Vuforia.UnityExtensions.Editor.dll (Location of the symbol related to previous error)
Assets/Vuforia/Editor/Scripts/Vuforia.UnityExtensions.Editor.dll (Location of the symbol related to previous error)
error CS1704: An assembly with the same nameVuforia.UnityExtensions' has already been imported. Consider removing one of the references or sign the assembly
F:/unity-2018.1/Unity/Editor/Data/PlaybackEngines/VuforiaSupport/Managed/Runtime/Vuforia.UnityExtensions.dll (Location of the symbol related to previous error)
Assets/Vuforia/Scripts/Internal/Vuforia.UnityExtensions.dll (Location of the symbol related to previous error)

Compilation failed: 2 error(s), 0 warnings

unity中有vuforia的dll包，删除这个路径F:/unity-2018.1/Unity/Editor/Data/PlaybackEngines/VuforiaSupport/Managed/Editor/Vuforia.UnityExtensions.Editor.dll (Location of the symbol related to previous error)
Assets/Vuforia/Editor/Scripts/Vuforia.UnityExtensions.Editor.dll下的文件重新生成一遍在引用试试，有时候在引用时引用了两遍就会出现这种情况。

检查你的unity是否内置了vuforia，再次引用必然会报错