We're running ASP.NET 2.0 on MS Server 2008 and IIS 7. During the last releases the app pool hasn't automatically been restarted after changes in the bin folder. It works like a charm on our test server but not on the live server. The site is browsable but runs with the logic of the old version of the updated dll.

One of the changes we have done lately is that one of the dll:s in the bin folder consists of other dlls that have been merged with ILMerge. Interop.ADODB.dll and Interop.CDO.dll is included in the merged dll. It is the user dll of the merged dll that is updated.

What can possibly hinder IIS from restarting the app pool although a file has changed in the bin folder?


Two things to check. Make sure that the folder than the /bin folder is in is marked as an application. If it's not then it's not considered an application folder.

If you're using a UNC path for content, or have a HUGE amount of files and folders, then the File Change Notification (FCN) may not be able to keep up. There's a registry key to change the behavior for FCN too, so the server administrators may have changed that.

  • The parent folder to bin is marked as an application. We're not using UNC path. There's only two dll's in the bin folder and noone has been tampering with the registry. Thanks for your answer but nothing of it solves our problem :( – Carl Björknäs Jun 27 '11 at 7:19
  • Rereading your thread, you mentioned an app pool restart. Deploying new code won't cause a full app pool recycle. It will cause an AppDomain recycle, but the worker process PID won't change. Here's a video describing that in detail: dotnetslackers.com/articles/iis/…. So, maybe it's doing what it's supposed to already. – Scott Forsyth - MVP Jun 27 '11 at 16:05
  • We didn't look at the PID, just the behaviour of the site and it was exactly like before we replaced one of the dll:s. After a manual recycle the behaviour changed... – Carl Björknäs Jun 29 '11 at 14:24
  • As you expect, it's not the norm to see that. Somehow the file change notification (FCN) isn't triggering. Any clues in Event Viewer in the hours leading up to it? You don't have in the hundreds of thousands or millions of files do you? That can throw off FCN. – Scott Forsyth - MVP Jun 29 '11 at 14:40

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