I got the following error when trying to figure out why I couldn’t start IIS 7 on Windows Server 2008 R2. I tried to start the World Wide Web Publishing Service but its dependency Windows Activation Service wouldn’t start. I got the following error in the Event Log:
The Windows Process Activation Service service terminated with the following error:
The data is invalid.
After doing some research, I found a good article here. But I still had the issue, it turned out that I had a valid applicationHost.config file but my C:\Windows\system32\inetsrv\config\schema\NetFx40_IIS_schema_update.xml file was corrupt and had invalid XML. So I was able to recover the XML file from the C:\inetput\history\schema folder. Fewl! Run all the services again and had no problems.