Hallo John Longney
Thanks for your input. My system is up and running smoothly again.
I found the solution here:
https://support.microsoft.com/en-us/help/4054517/windows-10-update-kb4054517
Regards, John (slagtand)
My system: Win10x64 Version 1709 / build 16299.98
UPDATE : My system is up-and-running after following the instructions (MS-site, above) ☺ ☺
It took just 10 minutes or so.
I sent following reply to Microsoft:
I managed to install the updates to my system (Win10 Home x64, version 1709; build 16299.98. @ i7 + 16GB ram) Have been struggling for 2 weeks now, resulting in a leak of storage area, drive C. After going through the instructions, I gained 49 GB back! Laptop is not in an reboot-Installing loop ☺ !
PLEASE DO update all other languages of support. I am form the Netherlands. THAT site does not point to this solution.