Mr_Cellophane Furthermore, when it's in Looping mode, I can pick any start to be the guide. but once I click the guide button it auto picks one for me, and then I can't select another.
ASIAIR v1.6 will try to use multi-star guiding if it could. It will not pick saturated stars and also will not pick stars that have poor signal to noise ratio.
Interestingly, you can pick a single star to guide (this was discussed in the Facebook forum, but not in this forum). What you do is to quickly tap on a different star immediately after it selects the multiple stars. You have only a short time window to do this, though.
This is different from v1.6 beta, when it will use a single star if you pick the star before you start guiding (that cross hair target icon). If you start guiding without picking a star, it will use multi-star.
For some reason, ZWO got rid of this (probably because they think it would confuse the beginners).
However, probably because of complaints from people who had found single star to be useful (primarily people with OAG or small guide scopes/insensitive cameras who cannot find enough guide stars to use multi-star guiding), that function is back in the currently running v1.6.1 Beta. The text in the guiding window (under "workflow") now says this:
Multi-stars wll be used for guiding by default except a star is selected manually in step 1.
If you need the single star guiding function badly, you might want to download the 1.6.1 beta, but I suspect it will be released soon (I don't see the beta note mentioning any pressing issues left).
As to why your mount won't move during the calibration phase, I have no idea. Be aware though, that calibrating close to the pole will not move the mount sufficienty in Right Ascension (the East-West movement) to detect sufficient movement on the guide plate. The PHD2 recommendation is to do all calibrations near the celestial equator before moving the mount to the imaging target. If you were trying to calibrate near the pole (say, declination greater than 75º), you may want to try moving further away from the pole to see if that helps.
Also check the "Calibration Step" field in the Guide Settings window. Increase that number if your mount does not move enough during calibration. You should aim for a "Calibration Step" number to give you about 12 steps during calibration. Accuracy suffers when there are too few steps, and you are just wasting time if there are many more steps than 12.