Cannot attach debugger to w3wp

Question

I'm debugging an ASP.NET application but sometimes cannot find w3wp neither in Visual Studio process list (Menu: Debug -> Attach to Process...) nor in task manager. I have selected 'Show processes from all users' and 'Show processes in all sessions' check boxes. When run the project from localhost, after an unhanded exception happens debugger would attach to w3wp (too late for me to step into code) !

Why I cannot see w3wp sometimes ?

Windows Server 2008 Enterprise Edition 64-bit, Visual Studio 2010

score 79 · Accepted Answer · edited Mar 12 '15 at 07:04

79

When you reset IIS or IIS is not running, you need to make a call to the server, when you hit the server for the first time the w3wp process starts.

edited Mar 12 '15 at 07:04

answered Nov 30 '10 at 11:37

Sandy

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Yes, making a call to localhost resolved the problem. This happened since I changed my home page from localhost to Google ! – Xaqron Nov 30 '10 at 11:43
Just hitting any page on the website hosted by your server should spin up the w3wp.exe (IIS application pool worker-process). – MikeTeeVee May 03 '12 at 18:12
It Works! After opening a web page attach to process. Not before! – gradosevic Apr 02 '14 at 15:30
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i know this answer was posted years ago, but if i could upvote this twice or more, i would :) – Eytch Jun 10 '14 at 13:59
I strongly agree with Eytch. :) Anyway, Thanks a lot for your answer. – Mohammad Mostafizur Rahman Mar 04 '18 at 06:56

score 7 · Answer 2 · answered Jun 23 '14 at 16:16

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THe same thing happened to me. After an update I couldnt find the W3WP! I realized that it didnt show all the processes. Checking the checkbox 'Show processes from all user' was required.

answered Jun 23 '14 at 16:16

R B

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score 5 · Answer 3 · edited May 04 '12 at 14:52

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Same thing was happening to me, when i remembered that IIS has an idle timeout! As above the proc w3wp is running, but VS2010 looks at it in the sleep state and thinks its not running, so dos'nt show it in the list...

spinning up IIS [calling a site served from locahost in your favourite web browser] reactivates IIS and suddenly VS can see the process [w3wp] now too

NOTE - must ask MS to ignore the sleep state of IIS/w3wp and if it is in sleep mode - cause it to automatically wake up!

thanks

edited May 04 '12 at 14:52

Darren

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answered Apr 19 '11 at 09:20

Anthony Leonard

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To anyone reading this answer... IIS doesn't have a 'sleep state'. The w3wp process is gone. A new w3wp process is started when it is needed. – Glen Little Oct 20 '16 at 19:08

score 3 · Answer 4 · answered Sep 11 '13 at 18:32

3

Quick fix for this, when debugging WCF services in Visual Studio:

Pop open your client app's web.config file.
Find the endpoint entry for the service that isn't appearing in Attach To Process.
Hit Ctrl+Click on the endpoint url, so that it loads the service window in Visual Studio's internal browser.

That's it. IIS will fire-up and you can now pop back over to your service and find W3WP.exe in the processes list.

Also, make sure "Show Processes From All Users" is checked.

answered Sep 11 '13 at 18:32

Jason Marsell

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In your solution item 3 does the job as the confirmed answer is saying. Same as `CRTL`+`Click` on a `localhost` link in `MS-Word`. – Xaqron Sep 11 '13 at 21:10
Agreed, @Xaqron. My reason for posting these steps was to give a quick solution, using a file (web.config) that's easy to access in the current project. – Jason Marsell Oct 22 '13 at 01:47
Ok, I know this question is ancient, but I am hoping someone can come back and help me out. I don't understand step 2. What am I looking for in the web.config? For me, w3wp.exe is not appearing in Attach to Process. What endpoint would I look for? – Casey Crookston Sep 18 '17 at 14:20
Okay, just to be extra clear, you're not opening your service's web.config file - you're opening the web.config of an app that *calls* your service. Find the endpoint of your service in that web.config and ctrl+click on it (which should pop open the Visual Studio browser) to activate it. Then, switch back over to your service project, open the "Attach to Process" dialog, click the "Show Processes From All Users" checkbox and you should see w3wp.exe now in the list. – Jason Marsell Sep 19 '17 at 15:31

score 2 · Answer 5 · answered Jun 01 '12 at 12:32

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I also encountered the same problem. Just build the project again. It would then show up the w3wp.exe in the attach process list.

answered Jun 01 '12 at 12:32

Hatjhie

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score 2 · Answer 6 · answered Nov 04 '13 at 19:26

Also when the attach to process window is open in the bottom left there is a checkbox 'Show processes from all user' make sure this check box is checked then it will show up. You may need to run visual studio as administrator to too. Hope this helps.

score 2 · Answer 7 · answered Oct 06 '15 at 08:16

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Make sure you run VS as an administrator.

answered Oct 06 '15 at 08:16

siphab

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DeveloperDan · Answer 8 · 2016-01-19T19:07:58.577

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Look closely at the URL of the page you are debugging in the off chance that it changed to a different server - something that may rarely happen but happened to me. This falls under the category of "check your assumptions".

edited Jan 19 '16 at 19:07

answered Jan 19 '16 at 18:58

DeveloperDan

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score 0 · Answer 9 · answered Feb 19 '17 at 16:33

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I don't how, but there appeared to be an extra application tied to the app pool I was using. Try creating a new app pool and point your application to the newly created app pool. Double check there is only 1 application with your new app pool.

answered Feb 19 '17 at 16:33

DeadlyChambers

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Cannot attach debugger to w3wp

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