This morning, while trying to debug our big ol’ web project in Visual Studio 2015 I encountered a problem – it held me up for a while so I wanted to quickly blog about the solution in case it hits you too. When hitting F5 to start debugging, Chrome launched but then immediately Visual Studio detached from IIS Express and showed the following error:

A process with the ID of <id> is not running

True enough, IIS Express wasn’t running…

Open Wide and Say ‘Ahh!’, Mr Windows

I ran a Repair on IIS Express 10.0 in case it was an issue with that, or the self-signed SSL certificate it uses to host web projects over a secure connection…. but still had the same problem.

I then created a brand new ASP.NET MVC 5 project and hit F5… but that ran fine. Hmm, curious. That let me know IIS Express was fundamentally OK, and the issue lay with the big ol’ web project.

Microsoft are usually pretty good at logging when things go wrong so I fired up eventvwr, the Windows Event Viewer, and saw the following  error being thrown by IIS Express:

The Module DLL C:\Program Files (x86)\Microsoft Web Tools\AspNetCoreModule\aspnetcore.dll failed to load. The data is the error

Strange… We don’t have any ASP.NET Core projects in that solution so why aspnetcore.dll is being loaded was beyond me. Furthermore, that path didn’t exist on my disk. Read more