Way back in Visual Studio 2005 Microsoft added a new debugger host, VSHost. The purpose, as advertised, was to speed up debugging by taking the hit for starting a debug session. The idea was that the host was started when you first began debugging and continued to run until you closed VS. This allowed VS to keep debugging information cached which sped up repeated runs of the debugging session. It only worked for managed applications but, for the time, greatly increased debugging startup. But there were problems with this approach. Firstly was that some apps simply didn’t work correctly with it. Microsoft provided a project debug setting that allowed you to disable the host in this case. Secondly it mucked with the whole debug process because VS started the host which emulated your process (it even had a config that matched your config). Thirdly, since it was a separate process, it would occasionally stop responding or crash which caused issues with the debugger.
Starting with VS 15 preview 5, the VS host process is gone. Microsoft has wisely optimized debugging startup times making the need for this process mute. So now running your app in the debugger is going to behave more naturally and, in theory, VS shouldn’t run into any more issues of disconnected processes. You can read more about this decision here.here