For some reasons the files aren’t being backed up, this is what I see -
The grey minus sign indicates that folder is unchecked in the Selective Sync settings in Dropbox. You can check this link for more info: https://www.dropbox.com/help/406
Could you please make sure that the Boxifier folder and its subfolders are checked in the Selective Sync settings on the computer where Boxifier is installed?
The files I showed you are on an external drive, so I don’t want them backed up to my pc, just to dropbox, but they aren’t being backed up (they were till now, but I changed a lot of files in one folder and the change isn’t showing on dropbox.com)
They are not being backed up to your Dropbox account because they are not checked in the Selective Sync settings in Dropbox. Checking them in the Selective Sync settings in Dropbox on the computer where Boxifier is installed will make them start syncing.
The files will not be downloaded to the Dropbox folder on the PC where Boxifier is installed. You can try checking them in the Selective Sync settings and convince yourself that this is the case.
Did you try checking them?