How do I permanently stop the Marshmallow update ??

[mhnac]

I simply do not want the Marshmallow update. My phone starts the update process, I Force Stop HtcDM (NOT HTC DM) , Clear Data and the update stops.
The following morning I see that HtcDM is no loger stopped and the Marsmallow update is 59% downloaded.

I Force Stop HtcDm, Clear Data and the vicious cycle continues.

How do I permanently stop this process ? What or Who turns HtcDM back on ????
PS
There is NOTHING in "Goggle Settings" or the play store that addresses this issue.

Please Help me in this matter.

 

[Ry]

Which (HTC) device?