Hello DavidPK. Thank you for your suggestion.
Unfortunately this was no solution as the Synaptics driver seems to have some odd proporties in relation to Windows Update. It isn´t visible in the Microsoft tool Show or Hide Updates. It also isn´t shown in the updates list in Control Panel/Programs&Features/View Installed Updates but it can be seen in Settings/Update and Security\Advanced options/View your update history as Synaptics driver update fo Synaptics PS/2 Port TouchPad. It is also shown as an installed program in Programs and Features as Synaptics Pointing Device Driver version 19.0.12.0. In the Device Manager the PS/2 mouse is presented as Synaptics PS/2 Port TouchPad. We use standard HP PS/2 mouses.
Do you have any idea how to make Mirosoft act, if they own this problem? It seems to be hard to actually reach someone there, who´s in charge.
BR Jonas