重新安装VS2010后，我收到了同样的错误信息。在我的情况下，IIS中的所有应用程序池都重新映射为4.0，因此VS2010无法确定在调试期间将自己附加到哪个池。在我的情况下，解决方案是手动删除几个池并将我的旧池重新映射回.net 2.0。我终于结束了，只有2个池指向.net 4.0（集成和经典）和2个池运行.net 2.0（集成和经典）。

I got the same error message after reinstalling VS2010. In my case all application pools in the IIS where remapped to run 4.0, so VS2010 was unable to figure out which pool to attach its self to during debugging. The solution in my case, was to manually delete few pools and remapping my older pools back to .net 2.0. I finally ended up, only having 2 pools pointing towards .net 4.0 (integrated and classic) and 2 pools running .net 2.0 (integrated and classic).