参见 这里

重建 nuget 包修复了它.转到 %USERPROFILE%/.nuget 并清除所有内容.

Rebuilding the nuget package fixes it. Go to %USERPROFILE%/.nuget and clear it all.

还有这里

@ericwj 根据网络工具团队的 joe 所说，这是一个已知问题.有一个包含错误引用的 BrowserLink 包版本，这显然是 .NET Core 1.1 CLI 安装程序附带的版本.但是，在 RC.3 中，我们从 Core 1.1 模板中删除了 BrowserLink，因此新项目应该不会出现问题.

@ericwj According to joe on web tools team, that’s a known issue. There was one build of the BrowserLink package that had bad references, and that’s apparently the one that shipped with the .NET Core 1.1 CLI installer. However, in RC.3, we removed BrowserLink from the Core 1.1 template, so it shouldn’t be an issue with new projects.