Why do inetinfo.exe, dllhost.exe and aspnet_wp.exe all start under debugger on themselves and I can't attach to either?

Question

I'm trying to debug an ASP.NET application. I've created a virtual directory in IIS, copied all the binaries and web.config there. When I pass request from the client program running on the same computer aspnet_wp.exe is started but then something goes wrong.

I want to attach to the process and try debug it. When I ask Visual Studio to "Attach to process" it displays a list of processes and aspnet_wp.exe, inetinfo.exe and dllhost.exe are all displayed grayed as if they are already debugged by some other program and so I can't attach to any of them.

I have tried to disable the "debug" option in web.config:

<system.web>
    <compilation debug="false">
    othersettings
</system.web>

but it didn't change the behavior.

What's happening and how do I make aspnet_wp, inetinfo and dllhost all start in such way I can attach a debugger to either of them?

Answer 1

The problem was caused by IIS Diagnostic Toolkit which I installed recently. Since it performs some magic sniffering on IIS it needs attaching as a debugger. I don't know which component of the toolkit is causing the problem.

After I removed the toolkit all the three processes start normally and I can attach Visual Studio debugger to any of them.