Grid wrong , Grid out of line, Snapping wrong

[GrangerMorton]

Hi, 
hopefully someone can help.
Illustrator is driving me nuts.
I have set a grid (every 60mm with 60 divisions) but illustrator won't snap to this grid. The key increment is set to 1mm yet it jumps 2mm.

The grid visual is out of line and shows lines every .5mm.
The grid doesn't line up with the rulers and the snap is to the grid not the ruler.

What am I doing wrong??

thanks

G

[GrangerMorton]

 

[Ton Frederiks]

I am not sure what you did, but I can reproduce it by moving the artboard and showing the grid.

If I double click the intersection of the rulers and zoom in or out it fixes the problem.