How to coordinate the clock when dual-booting with Windows

[Xen]

Xen schreef op 12-12-2017 13:53:

> I am going to check now what happens if I don't shut down. But instant
> mayhem :).

AND.... the problem is gone when I shut down without telling Linux 
first.

So for me the problem is created when Linux does its shutdown sequence.

It possibly thinks it has to restore the clock to something else?

I would have to check my shutdown log but there is usually not a lot in 
it I think.

So as far as I can say the problem has to do with one of the services 
getting STOPPED.

This service (for me) resets the time to UTC.