This weekend, I updated to the latest APCC version.
when using Maxim DL6.26, and an updated Win10.
I live in denmark (EU), and have learned early on (around 2014ish, I think) that in order to make APCC work properly I need to have the PC set to US number, time, and date format.
For some reason a recent Win update did reset the number, time and date format to my standard area settings (Danish, German etc.). This happens quite often.
Without noticing this, I did a platesolve corrected slew, and got an error message. Once I returned the PC back to US formats everything worked fine.
This is not a big deal, I just have to check the observatory computers assigned to my AP mounts, and ensure that they run US formats. 
Some of you living outside the US might benefit from this info, which is hereby shared.
Clear skies
Morten