We received notice on a server that the World Wide Web Publishing Service had stopped. This happened to be an Exchange 2010 server, so all webmail functionality stopped. I attempted to start the service manually but received an error that a dependency was unable to start. Reviewing the event logs, I saw that the dependency was the Windows Process Activation Service.
Unfortunately, the error was a bit unhelpful: “The Data is Invalid.”
As I scrolled through the event log, I came across another error that indicated what appeared to be corrupt XML data in a configuration file. This appeared as event 5172.
Sure enough, when I browsed to c:windowssystem32inetsrvconfigschema, the NetFX40_IIS_schema_update.xml file had been updated around the time webmail crashed.
Each time a change is made in IIS, Microsoft keeps a copy of the configuration files from before the change. Those can be found in c:inetpubhistory. From here, you will see a listing of configuration backups. In my case, I chose the latest copy and replaced the recently-updated version. After that, I attempted to start the World Wide Web Publishing Service, and it started right up!
Pay Attention to REPLACE the file and not rename it. if you will rename the updates file, and paste to the same folder the current file- the service will still try to point to the renamed file.