I've just migrated to a new dev machine, and when I launch my ASP.NET application, it starts fine, including Session_Start being called, and displays the WebForms login form (legacy, I know). But as soon as I click anywhere on that webpage, iisexpress terminates with exit code -1 (0xffffffff). It seems to skip both Session_End and Application_End, as no output is generated in the Output panel, from my System.Diagnostics.Debug.WriteLine(...) calls.
Any idea what might be happening or how I can research it? I'm unable to find anything useful on the web.
Update 2018-05-17: The problem has vanished.
Yesterday, after posting, I tried some options: Disable debug and continue, change to use Chrome rather than FF, start option changed from "current page" to "specific page" (index page) or "start URL" (also index page). The problem vanished.
This morning, I tried resetting those options to what I think they were originally, but am unable to reproduce the problem.
So, I can only assume there was some temporary problem on my system.