Reference mark not found Error

[KKann]

Has anyone ever encountered this Error? on a 7.10.7 SF. Is it not reading the scales properly? will this require another service call? (Just had hexagon here to fix a freak Y axis Motor on a 2 year old machine)
I get this error while homing the Z axis.

error.JPG

[neil.challinor]

It could be that the Z ram is too high prior to starting the homing cycle, resulting in the marker being missed. Before homing the machine, are you able to drive it at all using the jogbox? If you are, try driving it to a lower Z position before clicking OK to home the machine. Obviously, be very careful when driving the CMM prior to homing since the software limits are not enabled at this point and it will be possible to drive into the hard stops.

[acgarcia]

I get this mostly on my X axis on 1 of my tigos. Use medical grade alcohol and lint free cloth to clean the scale. Shut down and restart.

[KKann]

I had cleaned the Z scale after encountering this problem (with alcohol) but apparently not good enough. I focused more on the "QR" code looking things on the scale ( i thought i remembered a tech saying those were the limit encoders), and apparently that fixed it. The scale did not look dirty in that area, but whatever works.