Question : DefaultAppPool Crashes

I have a web application running on Windows Server 2003 R2 Enterprise Edition SP2 with IIS 6.0 that has been running well for a long time.  Today, I navigate to the page and receive a "Service Unavailable" error in the browser.  On the server, I notice several similar errors in the system event log:

A process serving application pool 'DefaultAppPool' terminated unexpectedly. The process id was '3148'. The process exit code was '0xffffffff'.

Application pool 'DefaultAppPool' is being automatically disabled due to a series of failures in the process(es) serving that application pool.

I have rebooted and run tasklist from a command line and then re-produced the problem but the PIDs do not exist in the previously run tasklist output.

Nothing in the W3SVC1 logs, but in the httperr1.log file I am seeing the following errors:
2009-12-10 21:01:54 10.224.225.97 4886 10.224.80.25 80 HTTP/1.1 GET / 503 1 AppOffline DefaultAppPool

I downloaded IISState from http://www.iisfaq.com/default.aspx?view=P197 and received the attached output.  Can anyone help?

Answer : DefaultAppPool Crashes

This is being caused by one of the Windows updates that was installed on Tuesday.  If you remove it for now, your websites will work.

Can be removed from Add/Remove programs etc.

I did some looking on the web after seeing this issue reported again, and others have also mentioned one of the updates breaks IIS.  This link has further details, plus the updates that were included from Tuesday:

http://serverfault.com/questions/93049/why-does-december-8th-2009-patch-tuesday-kill-iis-in-windows-server-2003