Recently I came across an error where OWA had stopped working on an Exchange 2010 server.
After a quick look in services I could see that the IIS Admin Service wasn’t running. So I tried a quick iisreset /restart command, but received the following error.
Back to Services again, and I could see that the World Wide Web Publishing Service wasn’t started. I tried to start the service but it failed to start.
I tried starting the Windows Process Activation Service, but it wouldn’t start and produced the following error message:
The Windows Process Activation Service terminated with the following error:
The data is invalid.
So I had a quick check in the event logs, and each time the Windows Process Activation Service tried to start it generated an Event ID 5172 Error message in the System Event log:
The Windows Process Activation Service encountered an error trying to read the configuration data from file ‘C:\Windows\system32\intsrv\schema\NetFx40_IS_schema_update.xml’, line number ‘1’. The error message is: ‘Configuration file is not well-formed XML’. The data field contains the error number.
The file size was 0 KB which and contained no data. On further investigation I had a quick look at the Windows update history and the issue occurred after Microsoft.Net Framework 4.5.2 for Windows Server 2008 R2 x64-based Systems (KB2901983) was installed.
Whenever a change is made in IIS a backup of the configuration is saved in the C:\inetpub\history folder. So I browsed to the last CFGHISTORY folder to take a look, and sure enough the NetFx40_IIS_schema_update.xml file was 4 KB in size.
I copied the NetFx40_IIS_schema_update.xml file from the C:\inetpub\history folder to the C:\Windows\System32\inetsrv\config\schema folder.
I was then able to run iisreset, at which point the WAS, World Wide Publishing and IIS Admin Services all started sucessfully.