Since this update was applied; we are unable to save files or create folders, through windows explorer.
Yes, I have. I even tried turning their permissions off and on again. I also rebooted the NAS.
Apparently it was just one folder, of course, the one we were all trying to access today. Somehow it was set to read only, and could not be changed from the Win 10 side. I copied all the files to a new folder, used the “Web File Viewer” to delete the old folder and it seems to be working now.