Media Library Folders looks for files in wp-content/uploads. You can change the location and name of the uploads folder according to the page Editing wp-config.php,
Actually not, this is basic wordpress functionality and is set up in
/wp-admin/options-media.php
looking at the one of the diagnostic reports available in the Media Library Folders Reset plugin, ‘Display Folder Data’, it shows some folders without a parent folder and this will result in a Javascript error when loading the folder tree.
Looking at the list, it is completely useless, since it displays files that do not exist. At least not with this path. For example
http://xxxx.online.de/files//homepages/xx/d12345/htdocs/WordPress/Pospiech/files/cpp
http://xxxx.online.de/files/ is a link to the folder as seen for the website visitor
/homepages/xx/d12345/htdocs/WordPress/Pospiech/ is the server folder to the wordpress website
files/cpp is a valid folder in the wordpress website structure.
I do not know what a parent folder means. Anyway I assume that as long as this list is displaying useless data the plugin will very likely not work. The question is how to fix it.
I change the upload folder to wp-content/files/ But that only changes the link to
http://xxxx.online.de/wp-content/files//homepages/xx/d12345/htdocs/WordPress/Pospiech/files/cpp
Also, according to the above mentioned report, there too many folders here because it scanning most of the site rather than just the place for Media Library images are stored.
Since it contains data not available from the folder tree, but only the database I wonder how this list is generated.
I aggre that is seems to scan the whole folder structure, but how can I ensure that it only scans the media folder. Currently it does not scan the media folder.