Take the 2-minute tour ×
Server Fault is a question and answer site for professional system and network administrators. It's 100% free, no registration required.

I have a Windows 7 machine (Windows version 6.1.7601 SP1 Build 7601) with IIS installed. At some point the installation appears to have become 'corrupted' in some way, as any requests are now met with the message:

Service Unavailable

HTTP Error 503. The service is unavailable.

In IIS manager IIS is started and the app pool I am using reports itself as 'Started', yet there is no w3wp.exe process listed in the process list in task manager (I am a local admin and have clicked the 'Show processes from all users' button.

I have enabled logging for the web site (at default location of %SystemDrive%\inetpub\logs\LogFiles), but this folder is empty. I am assuming that this log output is written by w3wp.exe as it handles requests (no w3wp.exe, no log file?).

Presumably there is another layer of request handling that is responsible for starting the worker processes, does thsi layer have log files I can check, and/or can I uninstall/re-install that layer?


share|improve this question
1) App Pool "Started" status means that it can serve/accept requests, but that does not reflect the status of the actual w3wp.exe processes. 2) %SystemDrive%\inetpub\logs\LogFiles -- this is location for web access logs. If w3wp is failed to start you will see nothing here -- these logs will be updated only with working worker process. Better check %SystemDrive%\inetpub\logs\FailedReqLogFiles instead. 3) Turn on and check detailed error message, not brief one; 4) If still nothing -- use Tracing module and trace exact place and reason for failure (not easy task IMHO). –  LazyOne Jun 27 '12 at 10:25
Further to LazyOne's comment above, Failed Request Tracing is the best tool to use to begin to diagnose 503 Service Unavailable errors: For more info see: learn.iis.net/page.aspx/266/… –  Kev Jun 27 '12 at 11:38
Thanks. I enabled Failed Request Tracing as described in the link, but there are no failed request logs being generated. Something higher up the stack of HTTP request handling seems to be broken (http.sys?). I am requesting static content and there doesn't appear to be any relevant errors or warning in the Windows event logs. –  locster Jun 27 '12 at 12:43

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.