How to troubleshoot HttpException Request timed out (ASP.NET 2.0 32-bit)

NOTE: The following steps apply to ASP.NET 2.0 (32 bit). They have not been tested in other versions of ASP.NET. For ASP.NET 4.0 64bit, please refer to:



The following warning may occur in application event logs:


This kind of issue is typically occurs when the ASP.NET request executes for a period of time longer than the maximum timeout period allowed for server-side code execution.

 This maximum timeout period can be set by executionTimeout attribute of httpRuntime element in config file. (The default value is 110 seconds in .Net 2.0)


How to reproduce


Create an ASPX page named as sleep.aspx. It will sleep for 20 seconds:

<%@ Page Language="C#" %>

<%@ import Namespace="System.Diagnostics" %>

<script runat="server">

    protected void Page_Load(object sender, EventArgs e)


        DateTime time = DateTime.Now;

        Response.Write(String.Format("Time: {0}:{1}:{2}", time.Hour, time.Minute, time.Second) +

            "\tCurrent process: " + Process.GetCurrentProcess().Id.ToString());


                Response.Write(String.Format("This application is running in {0}", System.Environment.Version.ToString()));






<title>ASP.NET Simple Page</title>


<body bgcolor="#FFFFFF">

<p><asp:label id="Message" runat="server" /></p>




Create a web.config and put it in the same folder as sleep.aspx. It sets the maximum timeout period to 5 seconds.

<?xml version="1.0" encoding="UTF-8"?>



                                <httpRuntime executionTimeout="5"/>




Use your browser to access sleep.aspx and you will receive “[HttpException (0x80004005): Request timed out.]” error message after a while. The corresponded warning will also appear in application event log.




You may notice that this “[HttpException (0x80004005): Request timed out.]” error message may not immediately appear in 5 seconds. Internally ASP.NET uses a Timer (an instance of System.Threading.Timer) to invoke the request cancelation process. This timer is fired once every 15 seconds. Therefore in reality the request can timeout at any time between 5 seconds and 20 seconds.

Please refer to


How to capture dump files for “[HttpException (0x80004005): Request timed out.]”


The typical *mistake* people may make is to configure a debugger to monitor HttpException and generate dump files while HttpException occurs.

In fact ASP.NET will throw ThreadAbortException when the request times out although it shows HttpException to the users.

It is not practicable to generate dump files for all ThreadAbortException. To troubleshoot this issue we have to set a breakpoint before the ThreadAbortException is thrown.

I used the following steps to capture dump files for this “[HttpException (0x80004005): Request timed out.]” error message.

Save the following text as aspnet_timeout.cfg and  put it under c:\.

<ADPlus Version='2'>

    <!-- Configuring ADPlus to log all first chance exceptions -->

    <!-- Will still create full dump for any type of second chance exceptions -->


   <keyword Name="loadbysos"> .loadby sos mscorwks </keyword>

   <keyword Name="GetJIT"> !name2ee System.web.dll System.Web.RequestTimeoutManager.CancelTimedOutRequests </keyword>

   <keyword Name="JITAddress"> .foreach /pS 0n12 ( record {!name2ee System.web.dll System.Web.RequestTimeoutManager.CancelTimedOutRequests}) { r $t1= ${record}; bp $t1+0x172 ".dump /ma /u ${AdpDumpDirEsc}\\Full Request timed out ${AdpProcName}_.dmp;g"; .printf"*breakpoint list*\n"; bl}        </keyword>




                <Option>  NoDumpOnFirst  </Option>

                <RunMode> CRASH </RunMode>




        <DebugActions> loadbysos; GetJIT; JITAddress </DebugActions>





Open a command prompt with *elevated administrator privileges* and change the current directory to the folder where Debugging Tools for Windows is installed (The default location is %programfiles%\Debugging Tools for Windows (x86)


Run the command:

%windir%\system32\inetsrv\appcmd list wp

You will get the PID of the worker process for the problematic application pool.


Then run the following command:

adplus.exe -c c:\aspnet_timeout.cfg -o <output folder> -p <pid of problematic apppool>

Where <output foder> is the existing folder where you want to save the dump files

There will be one cdb.exe window popped up. Please keep this window running because it is monitoring the problematic application pool. If “Request timed out” occurs, it will automatically generate the dump files.


How to find out which operation causes “Request timed out” from dump files


Use windbg to open the dump file. Then load sos

0:025> .loadby sos mscorwks


Dump all objects in the stack of the current thread. You will find System.Threading.Thread object:

0:025> !dso

OS Thread Id: 0x444 (25)

ESP/REG  Object   Name

eax      05baf5b0 System.Threading.Thread

ebx      05baf5b0 System.Threading.Thread

ecx      01c4f300 System.Web.RequestTimeoutManager+RequestTimeoutEntry

esi      01c4f300 System.Web.RequestTimeoutManager+RequestTimeoutEntry

0f1ff03c 05b33ad4 System.Web.Util.DoubleLinkList

0f1ff040 01c4b508 System.Collections.ArrayList

0f1ff044 05b3397c System.Web.RequestTimeoutManager

0f1ff064 01c4aa94 System.Threading.ContextCallback

0f1ff068 05b3397c System.Web.RequestTimeoutManager

0f1ff088 05b33b30 System.Threading._TimerCallback

0f1ff094 01c4b4e4 System.Threading.ExecutionContext

0f1ff0a0 01c4b4e4 System.Threading.ExecutionContext

0f1ff0a4 05b33b30 System.Threading._TimerCallback

0f1ff0b0 05b33b30 System.Threading._TimerCallback

0f1ff1c0 01c4b090 System.Collections.Hashtable+HashtableEnumerator

0f1ff25c 05b33b30 System.Threading._TimerCallback

0f1ff260 05b33b30 System.Threading._TimerCallback



Dump the information of System.Threading.Thread object and you will find the field DONT_USE_InternalThread:

0:025> !do 05baf5b0

Name: System.Threading.Thread

MethodTable: 0e3c10f8

EEClass: 0e17d994

Size: 56(0x38) bytes



      MT    Field   Offset                 Type VT     Attr    Value Name

0e3b1f08  400063f        4 ....Contexts.Context  0 instance 05b20528 m_Context

0e3bd818  4000640        8 ....ExecutionContext  0 instance 01c4d2c8 m_ExecutionContext

0e3c0b24  4000641        c        System.String  0 instance 00000000 m_Name

0e3c0f88  4000642       10      System.Delegate  0 instance 00000000 m_Delegate

0e3ba220  4000643       14    System.Object[][]  0 instance 00000000 m_ThreadStaticsBuckets

0e3c2cc0  4000644       18       System.Int32[]  0 instance 00000000 m_ThreadStaticsBits

0e3c3720  4000645       1c ...ation.CultureInfo  0 instance 00000000 m_CurrentCulture

0e3c3720  4000646       20 ...ation.CultureInfo  0 instance 00000000 m_CurrentUICulture

0e3c0740  4000647       24        System.Object  0 instance 00000000 m_ThreadStartArg

0e3c33ec  4000648       28        System.IntPtr  1 instance  1915fa8 DONT_USE_InternalThread

0e3c2d70  4000649       2c         System.Int32  1 instance        2 m_Priority

0e3c2d70  400064a       30         System.Int32  1 instance        5 m_ManagedThreadId

0e399740  400064b      16c ...LocalDataStoreMgr  0   shared   static s_LocalDataStoreMgr


Run !threads command to list all threads and you will find the corresponded thread (whose OS thread Id is dd4) which causes “Request timed out”:

0:025> !threads

ThreadCount: 7

UnstartedThread: 0

BackgroundThread: 7

PendingThread: 0

DeadThread: 0

Hosted Runtime: no

                                      PreEmptive   GC Alloc           Lock

       ID OSID ThreadOBJ    State     GC       Context       Domain   Count APT Exception

   8    1 1400 018ad710      8220 Enabled  05baea40:05baf074 018ac928     0 Ukn

  19    2 132c 018b8658      b220 Enabled  00000000:00000000 018ac928     0 MTA (Finalizer)

  22    3 16ec 018d7718    80a220 Enabled  00000000:00000000 018ac928     0 MTA (Threadpool Completion Port)

  23    4  830 018d7ee8      1220 Enabled  00000000:00000000 018ac928     0 Ukn

  24    5  dd4 01915fa8   380b220 Enabled  01c57b44:01c58fe8 018d8590     1 MTA (Threadpool Worker)

  25    6  444 01923d00   180b220 Disabled 01c4b604:01c4d008 018d8590     0 MTA (Threadpool Worker)

  14    7  180 01933348   880a220 Enabled  00000000:00000000 018ac928     0 MTA (Threadpool Completion Port)


Switch to the problematic thread and list the call stack. You will find the sleep function:

0:025> ~~[dd4]s

eax=0000002d ebx=00000000 ecx=00004e20 edx=00000000 esi=0edced40 edi=00000000

eip=777f96f4 esp=0edcecfc ebp=0edced64 iopl=0         nv up ei pl nz na po nc

cs=001b  ss=0023  ds=0023  es=0023  fs=003b  gs=0000             efl=00000202


777f96f4 c3              ret

0:024> !clrstack

OS Thread Id: 0xdd4 (24)

ESP       EIP    

0edcee4c 777f96f4 [HelperMethodFrame: 0edcee4c] System.Threading.Thread.SleepInternal(Int32)

0edceea0 015806e1 ASP.sleep_aspx.Page_Load(System.Object, System.EventArgs)

0edceedc 6d59a7ff System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr, System.Object, System.Object, System.EventArgs)

0edceeec 62562544 System.Web.Util.CalliEventHandlerDelegateProxy.Callback(System.Object, System.EventArgs)

0edcef00 6255ba44 System.Web.UI.Control.OnLoad(System.EventArgs)

0edcef14 6255ba83 System.Web.UI.Control.LoadRecursive()

0edcef2c 62557b34 System.Web.UI.Page.ProcessRequestMain(Boolean, Boolean)

0edcf084 62557764 System.Web.UI.Page.ProcessRequest(Boolean, Boolean)

0edcf0bc 62557691 System.Web.UI.Page.ProcessRequest()

0edcf0f4 62557626 System.Web.UI.Page.ProcessRequestWithNoAssert(System.Web.HttpContext)

0edcf100 62557602 System.Web.UI.Page.ProcessRequest(System.Web.HttpContext)

0edcf114 01580455 ASP.sleep_aspx.ProcessRequest(System.Web.HttpContext)

0edcf118 6255dad6 System.Web.HttpApplication+CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()

0edcf14c 6253132c System.Web.HttpApplication.ExecuteStep(IExecutionStep, Boolean ByRef)

0edcf18c 62b2583f System.Web.HttpApplication+PipelineStepManager.ResumeSteps(System.Exception)

0edcf190 62b1b96c [InlinedCallFrame: 0edcf190]

0edcf230 62b06071 System.Web.HttpRuntime.ProcessRequestNotificationPrivate(System.Web.Hosting.IIS7WorkerRequest, System.Web.HttpContext)

0edcf2a0 62bdb5e6 System.Web.Hosting.PipelineRuntime.ProcessRequestNotificationHelper(IntPtr, IntPtr, IntPtr, Int32)

0edcf2a4 62bdb7d7 [InlinedCallFrame: 0edcf2a4]

0edcf7f8 005522b4 [NDirectMethodFrameStandalone: 0edcf7f8] System.Web.Hosting.UnsafeIISMethods.MgdIndicateCompletion(IntPtr, System.Web.RequestNotificationStatus ByRef)

0edcf808 62bdb67d System.Web.Hosting.PipelineRuntime.ProcessRequestNotificationHelper(IntPtr, IntPtr, IntPtr, Int32)

0edcf88c 62bdb7d7 System.Web.Hosting.PipelineRuntime.ProcessRequestNotification(IntPtr, IntPtr, IntPtr, Int32)

0edcf98c 005522b4 [ContextTransitionFrame: 0edcf98c]

 Xinjin from APAC DSI

Comments (10)

  1. Excellent blog. Really helpful in rooting an elusive timeout issue.

    •  Velu
  2. Steven Holt says:


    I'd love to run this on 64-bit IIS 7 on Windows Server 2008R2. I'm running into an issue with the breakpoint address — bp $t1+0x172. I'm also running .Net 4.0.

    I get the following error:

    Couldn't resolve error at 'Address:; bp $t1+0xB9 ".dump /ma /u c:\crash\20120519_194201_Crash_Mode\Full Request timed out w3wp.exe_.dmp;g"; .printf"breakpoint listn"; bl'

    Is there a different address to try? Am I chasing the wrong error?


  3. Steven Holt says:

    Sorry, that error should read

    Couldn't resolve error at 'Address:; bp $t1+0x172 ".dump /ma /u c:\crash\20120519_194201_Crash_Mode\Full Request timed out w3wp.exe_.dmp;g"; .printf"breakpoint listn"; bl'

  4. Steven, this is address offset is for 32bit +ASP.NET 2.0 enviornment. Regarding 64bit + ASP.NET 4.0, the offset must be different and we will update this in future.

  5. Steven, the 64bit + ASP.NET 4.0 guideline has been provided, you may want to check our new post:…/how-to-troubleshoot-httpexception-request-timed-out-asp-net-4-0-64-bit.aspx

  6. dustpike says:

    hi, thanks alot for this blogpost, helped me to get a decent stacktrace and solve the problem!

  7. Jeff says:

    I tried this, but the results of the !dso cmd just shows 5 lines that all say System.AppDomainUnloadedException

  8. Jeff says:

    Actually disregard that previous post, It looks like it actually didn't work because I am running on 64-bit . . I should be focusing on the article for that.

  9. Rodrigo Saldes says:

    Desde Chile, mis agradecimientos por la explicación del problema.
    Saludos cordiales.

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