安装时候遇到
there was a problem validating the license because the Operating System identification seems to have changed
需要把旧的删除
C:\ProgramData\Unity
下面的ulf 删除 重启unity
点击Re-activate按钮
u3d 安装 license 证书问题
原文：http://www.cnblogs.com/liujiang04/p/7355481.html
