Hi, thanks for posting!
The nCrunch.Host process is something launched by the NCrunch VS Extension during shut down of VS. It is responsible for cleaning up any leftover workspaces created by NCrunch, as soon as the devenv.exe process has completely terminated. As such, this is actually the reverse of what you've described (devenv.exe is actually keeping the nCrunch.Host process alive).
A likely scenario is that there is a deadlock on VS exit. This could be caused by any plugin you may have installed (including NCrunch). If the problem is happening consistently for you, I think the first step would be to try uninstalling NCrunch to see if this makes any difference. This would confirm or deny whether NCrunch is the culprit.
Beyond this, the best way to identify the problem is to attach the VS debugger (of another VS process) onto devenv.exe after the process has hung during exit. Break into execution and check the list of running threads. Are there any threads that appear to be stuck in distinctive places inside managed code? If you can provide me with the names of any NCrunch methods responsible for hanging the threads, I should be able to troubleshoot the issue.
Thanks!
Remco