I had this error today with a new site I had uploaded from a local XAMPP server.
Pages and News Manager were throwing errors on changes.
The Data and Backup folders and files had the owner and group of the SFTP user I had used to upload the site.
I finally noticed that a new page had the owner www-data:www-data and permissions set to 0755 so I recursively changed these to folders ownership to www-data:www-data and permissions to 0755 and the error went away.
So spelling that out during the install check would be a great help to new users Shawn!
Now, my follow up question is how do I upload an existing site to the live server so that the owner is set to www-data:www-data?
Pages and News Manager were throwing errors on changes.
The Data and Backup folders and files had the owner and group of the SFTP user I had used to upload the site.
I finally noticed that a new page had the owner www-data:www-data and permissions set to 0755 so I recursively changed these to folders ownership to www-data:www-data and permissions to 0755 and the error went away.
So spelling that out during the install check would be a great help to new users Shawn!
Now, my follow up question is how do I upload an existing site to the live server so that the owner is set to www-data:www-data?