Thanks Naeem, I made sure that all those things were in place and they were already. Then I thought it was the Homegroup settings that were inexplicably removed during the upgrade. Replacing those settings worked for a day but the following day the same Network Drive not connecting at startup.
I seem to have solved it by instead choosing to Add a Network Location for the server's AC folder. This is a new option with W10 alongside the old option to Map a Network Drive. It has held up for a couple days. This option is only available under This PC.
![[Linked Image from amazingcharts.com]](http://amazingcharts.com/ub/attachments/usergals/2016/01/full-3802-834-capture.png)