Problem(s) Encountered:

Attempted to move the guide probe of the MIS to a guide star but got an error message in the MIS window that read: Communication problems with X and/or Y, check log.  When this happened, the Y box filled red and didn't move while the X value would move, but then the yellow box that appears next to the actual value when moving the probe remained yellow
instead of changing green. When I checked the log it read: gy=0.000000 Sensor Fault, both limits asserted.  I listened to the MIS on one of these moves and it didn’t sound unusual.

Conferred with Eric about this and he seemed to think it was something to do with the Y stage/limit
switch.

Solution:

The limit for the y-stage @ origin failed, in the closed position, causing the system to flag for both states being present (probe was in the other limit).  Swapped in a new limit switch and system is working again.  This switch seems to fail with fair frequency, which is a pain.  It is a small, ITW 1913 M (18-40421) switch.  Unfortunately, due to space limitations, I do not know if I can swap in anything larger.  But if anyone knows of a more robust alternative, I’d be glad to hear of it!