@JMH - Lurker!
@BHuber09
It's been a VERY interesting thread for me - thanks for the time you have put into it
As I said, it's the first time I've got this deep into this particular error - and it had a few surprises, as you realise.
One last thing you could do for me, is list the properties of the C:\Windows\ServiceProfiles\NetworkService folder.
To do this, please open an Admin Command Prompt window, and run the following command....
icacls C:\Windows\ServiceProfiles\* /save %UserProfile%\ACLFile.txt /T
This will place the file ACLFile.txt in the base folder of your USername - please zip it and post it.
It'll take me a few days, probably, to digest the content (if I don't get indigestion!) - but If I discover anything useful, I'll come back.
At the moment, my thoughts are obviously leaning towards a permissions problem - the registry seems to be OK.
It may be that the data has been moved somewhere outside the Windows structure or deleted completely, by some piece of malware or a disk problem, and the permssions have been changed so that it doesn't allow entry into the folder.
- you could try searching the whole disk for the file tokens.dat and see what gets found, if anything.
Either way,
good luck in your quest for a solution - make sure that you point MS at this thread, as it'll save a lot of time for them and you.
Thanks again you being so patient!