Hi William

My pcs do not have a 'Run as Administrator' option with the shift-right click. They do have a 'Repair' option and I clicked this on my office pc and voila! Planner installed correctly. Trying the same thing on the telescope pc did not change the '438' error. Since they were identical when bought, I conclude this is a Microsoft eccentricity or some sort of voodoo.

I can ignore this for now but it would be nice to have a reason.