Backup setting

Settings > Easy Watermark > General

I am unable to undelete the “Backup” setting. I do not want to save the original version of my images. When I click the checkbox beside “Backup”, the checkmark disappears. I click “Save Changes” at the bottom, sometimes the checkmark comes back and sometimes it doesn’t. But when I click on Settings > Easy Watermark > General again, the checkmark is back in the checkbox next to “Backup”.

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