Wacom Intuos Pro - Brush Stopped Working

I have been happily painting with my Intuos Pro PTH 851, but suddently the brush stopped working.

If I disable Ink; it then works without pressure sensitivty. 

It works fine in the Wacom Settings when I test pressure sensitity as it shows it is working.

Pressing the brush down in windows still acts like a mouse click.

Any ideas? I tried a restart of the drivers, the wacom service, and my Windows 10 install itself.

I am running the latest version of PS. I tried rolling back one version with no effect..