>I have four worker processes in an application pool. I can see that all of them are loaded. One of them is having worker process ID 1924. It has been running for a while. Then, I got this:
>
>Change in C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\2d1d00b7\abb5692d\hash\hash.web
>HostingEnvironment initiated shutdown
>HostingEnvironment caused shutdown
>
>After I got this, the worker process has been replaced by a new one.
>
>Anyone knows something about this log that I detected?

Happens when IIS recycles the process. What settings do you have for 'Recycling' ?

You can code in Application_End to discover the ShutDownReason - see http://stackoverflow.com/questions/5443356/how-to-tell-why-an-iis-application-pool-is-recycled (second answer)