This is a weird problem I have never experienced in all my Moodle life.
I have brought Moodle into my current workplace and am trying to set backup | backup_auto_active to enabled (or even manual for that matter) but whenever I make changes and choose save the page reloads and everything is set as the default including backup | backup_auto_active being disabled. (e.g. .../admin/settings.php?section=automated or .../admin/category.php?category=backups)
Automated tasks is on in Scheduled tasks and 'runs' but the logs state (as expected) that the automated backup status is INACTIVE.
I am the administrator for our Moodle and have not noticed any other problems with adjusting and saving other admin settings. Cron is working as expected and turning on developer debugging is showing no errors in the php error logs.
I can manually back up an individual course without an issue.
I am running Moodle 3.5.2+ (Build: 20181011) on Windows (which I have done for a decade without issue). This build is using MySQL 5.5 and php 7.2.
I've had a look at other forum posts but haven't managed to find something similar.
Help would be greatly appreciated
I have no experience on Windows, but did you check permissions on directory where automated backup should write files? Do your web server has permissions to write in this directory. Do you have some errors in windows log?