ADWS Broken after in-place upgrade from Server 2008 R2 to Server 2012 R2

Question

I performed an in-place upgrade from 64-bit Server 2008 R2 to Server 2012 R2.  This machine ran Active Directory Web Services. After the upgrade ADWS will not start. I get the following event log error:
Log Name:      Application
Source:        .NET Runtime
Date:          11/21/2014 3:23:02 PM
Event ID:      1026
Task Category: None
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      COMPUTER
Description:
Application: Microsoft.ActiveDirectory.WebServices.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.ServiceModel.CommunicationObjectFaultedException
Stack:
   at System.ServiceModel.Channels.CommunicationObject.Close(System.TimeSpan)
   at Microsoft.ActiveDirectory.WebServices.WindowsHostService.StartService(System.Object)
   at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
   at System.Threading.ThreadHelper.ThreadStart(System.Object)
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name=".NET Runtime" />
    <EventID Qualifiers="0">1026</EventID>
    <Level>2</Level>
    <Task>0</Task>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2014-11-21T20:23:02.000000000Z" />
    <EventRecordID>65596</EventRecordID>
    <Channel>Application</Channel>
    <Computer>COMPUTER</Computer>
    <Security />
  </System>
  <EventData>
    <Data>Application: Microsoft.ActiveDirectory.WebServices.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.ServiceModel.CommunicationObjectFaultedException
Stack:
   at System.ServiceModel.Channels.CommunicationObject.Close(System.TimeSpan)
   at Microsoft.ActiveDirectory.WebServices.WindowsHostService.StartService(System.Object)
   at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
   at System.Threading.ThreadHelper.ThreadStart(System.Object)
</Data>
  </EventData>
</Event>

Answer 1

I compared the registry with a working system but the Counters - and all other keys - looked fine.
At the same time as upgrading a DC a colleague was updating an unrelated server, and he started to see similar events in the event log (but for the Dell OpenManage Essentials service, not ADWS). The error was complaining about KERNELBASE.dll which set my
spider sense tingling. We knew that this server had Windows Updates pending. Fully updating it solved the problem on that server.
I solved the ADWS problem in the end by fully Windows Updating the DC. In particular, the ADWS Service started successfully after installing KB2919355 and rebooting. That also
'unlocked' a further 59 updates pending. 
After the in-place upgrade I always fully Windows Update but I'm 99% certain that KB2919355 did NOT show up when I did a Check for Updates straight after a reboot so I thought the DC was up-to-date. I then spent hours investigating the ADWS problem and rebooted
as part of the diagnostics. It was then that I noticed on the logon screen that there were updates pending...
Moral of the story? Windows Update, then Update again, and again, and again. The length of time it takes to Windows Update after an upgrade from 2008R2 to 2012R2 is painful though.