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Failing app pools after Windows update

Today I arrived at work noticing that ALL our IIS applications were failing. As this not only influences our test and production enviroment but also our TFS server, nobody was able to do any kind of work.

After checking out the system logs, I saw that a lot of updates where installed last weekend. It seems that the applications pools were unable to start after applying KB 973917 on Windows Server 2003 to add support for Extended Protection in Windows Authentication. The root cause of this issue is machines being in an unsupported state where SP1 version of IIS binaries exist on an SP2 installation. Product support has released KB 2009746 on how to resolve this issue. The summary of the resolution is to reinstall SP2 to such machines to update all IIS binaries to the SP2 version.

You can get SP2 for Windows Server 2003 from the appropriate link in the article here:

http://support.microsoft.com/kb/889100

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