No matter what I do, Windows 10 changes the folders that belong to my "Documents" library on reboot to the standard folders (specifically %userprofile%/documents and the OneDrive documents folder). I don't want either of these folders in the Documents library; when I make changes they last for a while but then revert on reboot. My network admin tells me we have no GPO's that touch this setting. I also see other postings in this forum with similar problems and no answers; for example this posting appears to be the same problem with no answer. Does anyone have any insight into how to fix this permanently?

Incidentally, my motivation for changing the Documents library folder membership is to change the default "save" location for most apps. As far as I can tell, the only practical way to do this is to change the Documents library and then set the default "save" and "public save" folder there, but if there is an alternative method to accomplish the same goal, I'm open to that as well.