Thanks all - just had the same problem as Richard several years ago! - crazy this way - No file changes or model updates etc. - could run sky flats without problems two months ago but now NO GO - checked the SkyX driver and sure enough tracking on/off was cleared. Anyway checked and now back to usual operation - running Win 11 this way and the only suspect is a change when the usual windows updates have been applied - wow!!!

cheers, Merv