I sent an email to Adam and Doug regarding this matter but have not heard back, so thought it prudent to put the problem in a thread. I have the camera connecting and cooling. When I go to calibrate the guider, the following occurs: 1 Take image, I get an image of the star field. Message Error in plug in callback (519), Error in guide camera plug in 2 Calibrate, first image taken in calibration sequence, moving mount stated but it goes no further. 3 Calibration goes no further. I waited 5 minutes without any change. The programme just stalls. Can this problem be corrected? I am eager to use the camera and final commissioning cannot go any further without this problem being resolved. I am using V6.20.