dynamiccally creating/deleting directories

I'm dynamically creating and deleting some directories. They are created in the folder ~/data/backup.

Creating and deleting works fine, however, as soon as I delete a directory, IIS recycles the sessionpool, all sessions are gone and the user needs to log in again.

The applicationend log

Code:

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_shutDownMessage=Directory rename change notification for 'D:\Websites\mysite.com'.
mysite.com dir change or directory rename
HostingEnvironment initiated shutdown
HostingEnvironment caused shutdown

_shutDownStack=  at System.Environment.get_StackTrace()
  at System.Web.Hosting.HostingEnvironment.InitiateShutdownInternal()
  at System.Web.Hosting.HostingEnvironment.InitiateShutdown()
  at System.Web.HttpRuntime.ShutdownAppDomain(String stackTrace)
  at System.Web.HttpRuntime.OnCriticalDirectoryChange(Object sender, FileChangeEvent e)
  at System.Web.FileChangesMonitor.OnSubdirChange(Object sender, FileChangeEvent e)
  at System.Web.DirectoryMonitor.FireNotifications()
  at System.Web.Util.WorkItem.CallCallbackWithAssert(WorkItemCallback callback)
  at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
  at System.Threading._ThreadPoolWaitCallback.PerformWaitCallbackInternal(_ThreadPoolWaitCallback tpWaitCallBack)
  at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback(Object state)

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is there anyway to prevend this for happening?